Develop Reference

System.Net.WebException: Error: ConnectFailure (Connection refused)

Im building an xamarin app and am Im trying to post to Web api with IP address of http://192.168.1.108:51457/api/Home. the api already accepts this ip address.i.e. I can run the api from that uri.I also know that the web api can recieve post request.
Not sure if connection is being refused because the IP address is logically inaccessible or there is some authorisation required. is there a solution to this?
stack trace:
at System.Net.Http.HttpClientHandler+<SendAsync>d__63.MoveNext () [0x004ab] in <7736395a6c71409691a34accfc621095>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Net.Http.HttpClient+<SendAsyncWorker>d__49.MoveNext () [0x000ca] in <7736395a6c71409691a34accfc621095>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at App.Registration+<RegistrationFrom>d__1.MoveNext () [0x00184] in C:\Users\User\source\repos\App\App\App\Registration.xaml.cs:49
inner Exception: `**Error: ConnectFailure (Connection refused)"**`
at System.Net.HttpWebRequest.EndGetRequestStream (System.IAsyncResult asyncResult) [0x0003a] in <6c708cf596db438ebfc6b7e012659eee>:0
at System.Threading.Tasks.TaskFactory`1[TResult].FromAsyncCoreLogic (System.IAsyncResult iar, System.Func`2[T,TResult] endFunction, System.Action`1[T] endAction, System.Threading.Tasks.Task`1[TResult] promise, System.Boolean requiresSynchronization) [0x0000f] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Net.Http.HttpClientHandler+<SendAsync>d__63.MoveNext () [0x002e7] in <7736395a6c71409691a34accfc621095>:0

The empty string '' is not a valid local name. - Xamarin Forms PCL SOAP request call

I am trying to make a SOAP request and I am catching an Exception, you can see it below. (I am not consuming WCF)
Maybe someone had similar issues and knows how to solve it? Thanks in advance.
{System.ArgumentException: The empty string '' is not a valid local name.
at (wrapper managed-to-native) System.Object:__icall_wrapper_mono_delegate_end_invoke (object,intptr)
at (wrapper delegate-end-invoke) :end_invoke_object__this___object[]&_IAsyncResult (object[]&,System.IAsyncResult)
at System.ServiceModel.MonoInternal.ClientRuntimeChannel.EndProcess (System.Reflection.MethodBase method, System.String operationName, System.Object[] parameters, System.IAsyncResult result) [0x0001f] in <475dec2c1fe44b95bbfbd21b550b63f8>:0
at System.ServiceModel.ClientBase1+ChannelBase1[TChannel,T].EndInvoke (System.String methodName, System.Object[] args, System.IAsyncResult result) [0x00045] in <475dec2c1fe44b95bbfbd21b550b63f8>:0
at App3.AscoTms.imcwpPortTypeClient+imcwpPortTypeClientChannel.EndLogin (System.IAsyncResult result) [0x00008] in C:\Users\georgij.nebudrov\source\repos\App3\App3\App3\Connected Services\AscoTms\Reference.cs:3833
at App3.AscoTms.imcwpPortTypeClient.App3.AscoTms.imcwpPortType.EndLogin (System.IAsyncResult result) [0x00001] in C:\Users\georgij.nebudrov\source\repos\App3\App3\App3\Connected Services\AscoTms\Reference.cs:3088
at App3.AscoTms.imcwpPortTypeClient.EndLogin (System.IAsyncResult result) [0x00001] in C:\Users\georgij.nebudrov\source\repos\App3\App3\App3\Connected Services\AscoTms\Reference.cs:3093
at App3.AscoTms.imcwpPortTypeClient.OnEndLogin (System.IAsyncResult result) [0x00001] in C:\Users\georgij.nebudrov\source\repos\App3\App3\App3\Connected Services\AscoTms\Reference.cs:3103
at System.ServiceModel.ClientBase1+<>c__DisplayClass39_0[TChannel].<InvokeAsync>b__0 (System.IAsyncResult ar) [0x00006] in <475dec2c1fe44b95bbfbd21b550b63f8>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at System.Runtime.CompilerServices.TaskAwaiter1[TResult].GetResult () [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at App3.MainPage+d__2.MoveNext () [0x00081] in C:\Users\georgij.nebudrov\source\repos\App3\App3\App3\MainPage.xaml.cs:47 }

The type initializer for 'Microsoft.WindowsAzure.Storage.CloudStorageAccount' threw an exception error in Xamarin.forms

I'm working on AzureStorage cloud solution provided by Xamarin.
https://developer.xamarin.com/guides/xamarin-forms/cloud-services/storage/azure-storage/
And this is what I got in GetContainer() method.
The type initializer for
'Microsoft.WindowsAzure.Storage.CloudStorageAccount' threw an
exception
I applied my connection string in the sample project and it worked, but not in my own project.
Has anyone ever faced this issue? Please help me.
Thanks in advance.
Error message :
System.TypeInitializationException: The type initializer for 'Microsoft.WindowsAzure.Storage.CloudStorageAccount' threw an exception. ---> System.NotImplementedException: The method or operation is not implemented.
at Microsoft.WindowsAzure.Storage.CloudStorageAccount.Setting (System.String name, System.String[] validValues) [0x00000] in <667a5fa37f124e50ab7a68ecb3437b13>:0
at Microsoft.WindowsAzure.Storage.CloudStorageAccount..cctor () [0x00000] in <667a5fa37f124e50ab7a68ecb3437b13>:0
--- End of inner exception stack trace ---
at MyTenantWorld.AzureStorage.GetContainer (MyTenantWorld.ContainerType containerType) [0x00020] in <9816076ee17d42efaf1050c5169a4310>:0
at MyTenantWorld.AzureStorage+<UploadFileAsync>d__3.MoveNext () [0x0001a] in <9816076ee17d42efaf1050c5169a4310>:0
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at MyTenantWorld.SettingsPage+<SaveData>d__20.MoveNext () [0x00309] in <9816076ee17d42efaf1050c5169a4310>:0
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at Android.App.SyncContext+<>c__DisplayClass2_0.<Post>b__0 () [0x00000] in <d855bac285f44dda8a0d8510b679b1e2>:0
at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in <d855bac285f44dda8a0d8510b679b1e2>:0
at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in <d855bac285f44dda8a0d8510b679b1e2>:0
at at (wrapper dynamic-method) System.Object:a4fed05a-cd7a-4756-85bb-5dd975374042 (intptr,intptr)

As the GetContainer method defined under AzureStorage.cs as follows:
static CloudBlobContainer GetContainer(ContainerType containerType)
{
var account = CloudStorageAccount.Parse(Constants.StorageConnection);
var client = account.CreateCloudBlobClient();
return client.GetContainerReference(containerType.ToString().ToLower());
}
It seems that the error was thrown by CloudStorageAccount.Parse, but from BergQuester's link about CloudStorageAccount.Parse, we could find that this error is not from the predictable exceptions.
From your stack trace, we could find the error was thrown at Setting(string name, params string[] validValues) from CloudStorageAccount.cs. I used WindowsAzure.Storage 8.3.0 and tested it under my BruceChen_Mobile.UWP project and PCL project, it could work as expected with my azure storage connection string.
I applied my connection string in the sample project and it worked, but not in my own project.
I would recommend you checking the packages between your application and the xamarin-forms-samples. Or you could provide a reproducible sample project for us to narrow this issue.

I fixed this issue on mine by adding a reference to the WindowsAzure.Storage nuget package from my native projects (not just in the PCL project), as it requires some native implementations that are defined in these references.

Xamarin async Http Client

I've got a problem in my Xamarin Project: When I try to get a JsonString from a Webpage, via HttpClient.GetStringAsncy does my app crash. Here is the StackTrace of the error:
at System.Net.Http.HttpClientHandler+d__63.MoveNext () [0x00479] in :0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in :0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in :0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in :0
at System.Net.Http.HttpClient+d__49.MoveNext () [0x000ca] in :0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in :0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in :0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in :0
at System.Net.Http.HttpClient+d__54.MoveNext () [0x0007d] in :0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in :0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in :0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in :0
at MRKrauchthal.Pages.GameDetailPage+d__13.MoveNext () [0x00057] in E:\Visual Studio Projects\MRKrauchthal\MRKrauchthal\MRKrauchthal\Pages\GameDetailPage.xaml.cs:99
e.InnerException
{System.Net.WebException: Error: SecureChannelFailure (The authentication or decryption has failed.) ---> System.IO.IOException: The authentication or decryption has failed. ---> System.IO.IOException: The authentication or decryption has failed. ---> Mono.Security.Protocol.Tls.TlsException: The authentication or decryption has failed.
at Mono.Security.Protocol.Tls.RecordProtocol.EndReceiveRecord (System.IAsyncResult asyncResult) [0x00037] in :0
at Mono.Security.Protocol.Tls.SslClientStream.SafeEndReceiveRecord (System.IAsyncResult ar, System.Boolean ignoreEmpty) [0x00000] in :0
at Mono.Security.Protocol.Tls.SslClientStream.NegotiateAsyncWorker (System.IAsyncResult result) [0x00071] in :0
--- End of inner exception stack trace ---
at Mono.Security.Protocol.Tls.SslClientStream.EndNegotiateHandshake (System.IAsyncResult result) [0x00032] in :0
at Mono.Security.Protocol.Tls.SslStreamBase.AsyncHandshakeCallback (System.IAsyncResult asyncResult) [0x0000c] in :0
--- End of inner exception stack trace ---
at Mono.Security.Protocol.Tls.SslStreamBase.EndRead (System.IAsyncResult asyncResult) [0x0004b] in :0
at Mono.Net.Security.Private.LegacySslStream.EndAuthenticateAsClient (System.IAsyncResult asyncResult) [0x0000e] in :0
at Mono.Net.Security.Private.LegacySslStream.AuthenticateAsClient (System.String targetHost, System.Security.Cryptography.X509Certificates.X509CertificateCollection clientCertificates, System.Security.Authentication.SslProtocols enabledSslProtocols, System.Boolean checkCertificateRevocation) [0x0000e] in :0
at Mono.Net.Security.MonoTlsStream.CreateStream (System.Byte[] buffer) [0x0007b] in :0
at System.Net.WebConnection.CreateStream (System.Net.HttpWebRequest request) [0x00073] in :0
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.EndGetResponse (System.IAsyncResult asyncResult) [0x00058] in :0
at System.Threading.Tasks.TaskFactory`1[TResult].FromAsyncCoreLogic (System.IAsyncResult iar, System.Func`2[T,TResult] endFunction, System.Action`1[T] endAction, System.Threading.Tasks.Task`1[TResult] promise, System.Boolean requiresSynchronization) [0x0000f] in :0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in :0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in :0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in :0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in :0
at System.Net.Http.HttpClientHandler+d__63.MoveNext () [0x0041e] in :0 }
The Code looks like this:
private async Task SetImage(int id, string teamName, Xamarin.Forms.Image image)
{
try
{
HttpClient httpClient = new HttpClient();
obj = JsonConvert.DeserializeObject<JsonImage>(await httpClient.GetStringAsync("www.linkToImage.com").ConfigureAwait(false));
}
catch (Exception e) {
test.Text = e.StackTrace;
}
}
I hope someone can help me :D
Best Regards

There is some problem with the default SSL/TLS implementation in Xamarin.Android. You can go to Android Project settings->Android Options->Advanced->SSL/TLS implementation and change to Native TLS 1.2+

Xamarin App crashes calling HTTPS

I created a simple Xamarin.Forms App to check HTTPS using https://jsonplaceholder.typicode.com/.
But the App crashes using HTTPS.
public RestService() {
client = new HttpClient();
client.MaxResponseContentBufferSize = 256000;
}
public async Task<List<Item>> RefreshDataAsync() {
string url = "http://jsonplaceholder.typicode.com/posts";
// Crash using this URL
//string url = "https://jsonplaceholder.typicode.com/posts";
var uri = new Uri(string.Format(url, string.Empty));
List<Item> Items = new List<Item>();
var content = await client.GetStringAsync(uri);
Items = JsonConvert.DeserializeObject<List<Item>>(content);
return Items;
}
}
Is it a problem with the website or httpClient or do I do somethin wrong ?
Thats the Exception
{System.Net.Http.HttpRequestException: An error occurred while sending the request ---> System.Net.WebException: Error: SecureChannelFailure (The authentication or decryption has failed.) ---> System.IO.IOException: The authentication or decryption has failed. ---> System.IO.IOException: The authentication or decryption has failed. ---> Mono.Security.Protocol.Tls.TlsException: The authentication or decryption has failed.
at Mono.Security.Protocol.Tls.RecordProtocol.EndReceiveRecord (System.IAsyncResult asyncResult) [0x00037] in <d2bf9ddce2b945f79db1e7c4354bafea>:0
at Mono.Security.Protocol.Tls.SslClientStream.SafeEndReceiveRecord (System.IAsyncResult ar, System.Boolean ignoreEmpty) [0x00000] in <d2bf9ddce2b945f79db1e7c4354bafea>:0
at Mono.Security.Protocol.Tls.SslClientStream.NegotiateAsyncWorker (System.IAsyncResult result) [0x00071] in <d2bf9ddce2b945f79db1e7c4354bafea>:0
--- End of inner exception stack trace ---
at Mono.Security.Protocol.Tls.SslClientStream.EndNegotiateHandshake (System.IAsyncResult result) [0x00032] in <d2bf9ddce2b945f79db1e7c4354bafea>:0
at Mono.Security.Protocol.Tls.SslStreamBase.AsyncHandshakeCallback (System.IAsyncResult asyncResult) [0x0000c] in <d2bf9ddce2b945f79db1e7c4354bafea>:0
--- End of inner exception stack trace ---
at Mono.Security.Protocol.Tls.SslStreamBase.EndRead (System.IAsyncResult asyncResult) [0x0004b] in <d2bf9ddce2b945f79db1e7c4354bafea>:0
at Mono.Net.Security.Private.LegacySslStream.EndAuthenticateAsClient (System.IAsyncResult asyncResult) [0x0000e] in <a547bd0d78184f26ab08d022f013c1e1>:0
at Mono.Net.Security.Private.LegacySslStream.AuthenticateAsClient (System.String targetHost, System.Security.Cryptography.X509Certificates.X509CertificateCollection clientCertificates, System.Security.Authentication.SslProtocols enabledSslProtocols, System.Boolean checkCertificateRevocation) [0x0000e] in <a547bd0d78184f26ab08d022f013c1e1>:0
at Mono.Net.Security.MonoTlsStream.CreateStream (System.Byte[] buffer) [0x0007b] in <a547bd0d78184f26ab08d022f013c1e1>:0
at System.Net.WebConnection.CreateStream (System.Net.HttpWebRequest request) [0x00073] in <a547bd0d78184f26ab08d022f013c1e1>:0
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.EndGetResponse (System.IAsyncResult asyncResult) [0x00058] in <a547bd0d78184f26ab08d022f013c1e1>:0
at System.Threading.Tasks.TaskFactory`1[TResult].FromAsyncCoreLogic (System.IAsyncResult iar, System.Func`2[T,TResult] endFunction, System.Action`1[T] endAction, System.Threading.Tasks.Task`1[TResult] promise, System.Boolean requiresSynchronization) [0x0000f] in <3fd174ff54b146228c505f23cf75ce71>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Net.Http.HttpClientHandler+<SendAsync>d__63.MoveNext () [0x003e6] in <b696532a7c264e5e866cb15a1b40a4a4>:0
--- End of inner exception stack trace ---
at System.Net.Http.HttpClientHandler+<SendAsync>d__63.MoveNext () [0x00449] in <b696532a7c264e5e866cb15a1b40a4a4>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Net.Http.HttpClient+<SendAsyncWorker>d__49.MoveNext () [0x000ca] in <b696532a7c264e5e866cb15a1b40a4a4>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Net.Http.HttpClient+<GetStringAsync>d__55.MoveNext () [0x0007d] in <b696532a7c264e5e866cb15a1b40a4a4>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at getWeather.RestService+<RefreshDataAsync>d__2.MoveNext () [0x0006e] in C:\Users\afelde\documents\visual studio 2017\Projects\getWeather\getWeather\getWeather\RestService.cs:30 }

That Post on Xamarin.Forum also solve the Issue without installing any Nuget Packages :
As #SvetlomirKalitsov describes, the two settings below take care of
the issue:
HttpClient implementation -> AndroidClientHandler SSL/TLS
implementation -> Native TLS 1Here is where I made the mistake: There
are two pretty similar options: Native TLS 1.2+ which is the correct
one, and Default (Native TLS 1.2+). This second one (Default) will
fail. Make sure to select the non-default one; in other words, make
sure to force that option instead of relying on the Default.
A bit of background info: XA_HTTP_CLIENT_HANDLER_TYPE environment
variable on Xamarin.Android
Thanks #SvetlomirKalitsov

I found a post about your issue (https://forums.xamarin.com/discussion/10405/the-authentication-or-decryption-has-failed-in-the-web-request)
Here in the comments you will find someone suggesting to use the package modernhttpclient
The way to work with this package:
HttpClient client = new HttpClient(new NativeMessageHandler());
The NativeMessagehandler will solve the certifcations issue ( since u using https it gave a authentication error, this will solve it)
For the rest you can use the client as you were already using it.
Good luck