Develop Reference

Xamarin/Mono TLS Exception

I am putting together a Xamarin Android project and am trying to build a small app that makes calls to an API. The Xamarin project creates an instance of an ApiWrapper class that I have in another solution and that class is what makes the Http calls (not sure if that's important or not).
The stack trace that I keep getting at runtime is pasted below:
06-25 12:36:13.696 E/mono-rt ( 3365): [ERROR] FATAL UNHANDLED 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.
Here's what I've tried so far:
I have tried installing the ModernHttpClient and passing in the NativeMessageHandler into the constructor of HttpClient() with no success.
Made sure my app has INTERNET permissions
Added a custom validator class that returns true and gets passed into ServicePointManager.ServerCertificateValidationCallback
Run both mozroots and cert-sync to try and pull in the proper certificates for the site.
Also, just to be clear, I have a test project that is calling that same ApiWrapper class only through .NET's network stack and it's having no trouble with the encryption and is working properly.
I'm out of ideas and am struggling here. Any suggestions are very helpful! Thanks.

I had the same issue. Integration test was able to call the service and passed but running the code from the Android emulator threw that error. Also tried all the steps you outlined above.
What finally worked for me was changing the settings of the Android project. Right click on the project and click Properties. Go to Android Options and click the Advanced button.
Set..
HttpClient implementation -> Android
SSL/TLS implementation -> Native TLS 1.2+

ADOMD Connection Error

I am receiving the following error from ADOMD while trying to connect to my SSAS Server.
An unhandled exception of type 'System.Xml.XmlException' occurred in
Microsoft.AnalysisServices.AdomdClient.dll
Additional information: Element 'return' was not found. Line 5,
position 2.
I can confirm the following:
My Connection String Is:
Data Source=<MyServer>;Catalog=<My SSAS DB>; UID=<MyDomain>\<MyDomainUser>;PWD=<MyPassword>;
I can confirm that my connection string is correct ( or at least the data I am using in the connection string above is correct). If I change any part of the connection string to an incorrect value the ADOMDConnection will return "Cannot connect to server". I have also looked at the audit logs on the server itself and confirm that I am successfully logging onto the server. And the contrary, with incorrect credentials the server logs confirm a failed login.
I am trying to connect to SSAS 2014 Enterprise
The failed connection returns within a few seconds. A few posts out on the internet suggest increasing the Connection Timeout property. This does not seem to be my issue as I have increased it to 120 and its failing within 5.
I am using ADOMD 12.0 Runtime 2.0.50727
My domain user is a domain admin and has been added to an admin role in the SSAS.
Im not sure what else could be wrong or how to debug this or is this a known bug in ADOMD?
Any advice would greatly appreciated.
thanks!
Jason

This happens routinely when the version of the ADOMD client DLL is not a version that matches the target version of the server instance. For example, Azure Analysis Services as of 09/13/2017 does not work with Microsoft.AnalysisServices.AdomdClient.dll version 13. Only version 14 and above.
For reference, the ADOMD DLL for Azure Analysis Service is available in the link below:
https://learn.microsoft.com/en-us/azure/analysis-services/analysis-services-data-providers
Double check to make sure the client DLL is the exact version needed for the target server instance. That solved this exact issue in my case.

Cannot connect to Kafka running on a virtual machine

I installed kafka_2.10-0.8.1.1 on a Ubuntu 12.04 (Linux ubuntu 3.8.0-44-generic) hosted by vmware player 6.0.3 build-1895310. On the host machine (Windows 8) I am using the C# client from https://github.com/Jroland/kafka-net. The ip of the kafka machine is correctly configured in C# code, the topic "test" is accordingly created in kafka etc. I get the following messages:
No connection to:http://:9092/. Attempting to re-connect...
Type a message and press enter...
Awaiting message from: http://:9092/
BrokerRouter: Refreshing metadata for topics: test
Failed re-connection to:http://:9092/. Will retry in:1000
Failed re-connection to:http://:9092/. Will retry in:2000
Failed re-connection to:http://:9092/. Will retry in:4000
The same client connects to a physical linux machine with kafka.
I would like to be able to develop with kafka running as a virtual machine. How could I solve the communication issue?
Thanks

I never used the c# version, but is your producer configure correctly?
From the error message, it seems that it doesn't have the IP/DNS configured...
No connection to:http://:9092/

C# cannot access webservice that requires a client certificate from within the server

I have a webservice on a IIS website that requires a client certificate, my certificate is self signed and I can access the website from my dev computer without any warning after installing all the certificates issued/required, my problem is that I need to access a webservice from within the server and it's not working, I can do that from my dev machine by loading the certificate pfx file but on the server it will bomb, I already have the application pool the rights to access the certificate on the store but still no go, I appreciate any advice.
Thanks
On the dev machine this code works:
svc.ClientCertificates.Add(new System.Security.Cryptography.X509Certificates.X509Certificate2(Server.MapPath("Certs/MyFile.pfx"), "mypfxpassword"));
but that codes bombs on the server with:
System.Security.Cryptography.CryptographicException.ThrowCryptographicException(Int32 hr) at System.Security.Cryptography.X509Certificates.X509Utils._LoadCertFromFile(....
so I tried this code on the server:
X509Certificate2 cert = new X509Certificate2(Server.MapPath("Certs/MyFile.pfx"),
"mypfxpassword",
X509KeyStorageFlags.MachineKeySet);
svc.ClientCertificates.Add(cert);
and there's a new error:
"Could not establish trust relationship for the SSL/TLS secure channel."
I already tried this
winhttpcertcfg.exe -g -c LOCAL_MACHINE\My -s MyCertName -a "MYMACHINENAME\Name Of App Pool"
and this
ICACLS /grant "IIS AppPool\DefaultAppPool":R
I replaced the parameters on the command with my server paramaters and they executed successfully but still no go with "Could not establish trust relationship for the SSL/TLS secure channel.".
Any help is much appreciated.
Thanks

How I got it working.
Errors:
Could not create SSL/TLS secure channel - Could the problem be a proxy
server?
Could not establish trust relationship for the SSL/TLS secure
channel"
1) IIS
Open IIS
Select Application Pools
Select your pool
Click "Advanced Settings"
Set "Load User Profile" to "True" (mine was set to False)
2) Code Fix (required cause client certificate is self-signed and .NET doesn't trust that
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
Code thanks to this website, copied code from Matt Probstfeld II's comment.

Error starting ASP.NET State Service

I get the following error when trying to start the ASP.NET State Service:
Windows could not start the ASP.NET State Service service on Local Computer.
Error 2: The system cannot find the file specified.
Everything I found on google told me to go to the %windir%\Microsoft.NET\Framework\v1.1.4322 folder at the command prompt, and then type the following command: aspnet_regiis.exe -ir
which I did and didn't solve the problem. The path to the executable in my case is 2.0: C:\Windows\Microsoft.NET\Framework\v2.0.50727\aspnet_state.exe.
So I tried the same comand on the v2 folder and I get the error:
"An attempt was made to load a program with an incorrect format".
thanks in advace for any help

As stated here, it's trying to load the 32-bit version while you need the 64-bit. If this is applicable, open RegEdit (own risk and so on) and change HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\ImagePath
from %SystemRoot%\Microsoft.NET\Framework\v2.0.50727\aspnet_state.exe to %SystemRoot%\Microsoft.NET\Framework64\v2.0.50727\aspnet_state.exe.

You not need reinstall this service.
Just find in services "ASP.NET State Server" and start it.
Also you can set up to start this service automaticaly in preferences.