I am running an ASP.Net application on windows azure and I need to send an email from it. I am trying to send it using my gmail account as follows, however when I attempt to send it, I get the following error:
The SMTP server requires a secure connection or the client was not
authenticated. The server response was: 5.5.1 Authentication Required.
Learn more at
The code:
private static readonly string EMAIL_ADDRESS = "mymail#gmail.com";
private static readonly string EMAIL_FROM = "MY FROM NAME";
private static readonly string EMAIL_PASS = "my Password";
private static readonly string EMAIL_HOST = "smtp.gmail.com";
private static readonly int EMAIL_PORT = 587;
private static readonly bool EMAIL_SSL = true;
private static readonly SmtpDeliveryMethod EMAIL_DELIVERY_METHOD = SmtpDeliveryMethod.Network;
private static readonly bool EMAIL_DEFAULT_CREDENTIALS = false;
public static void SendEmail(string recipientEmail, string subject, string body) {
var fromAddress = new MailAddress(EMAIL_ADDRESS, EMAIL_FROM);
var toAddress = new MailAddress(recipientEmail, "MY CLIENT NAME");
var smtp = new SmtpClient {
Host = EMAIL_HOST,
Port = EMAIL_PORT,
EnableSsl = EMAIL_SSL,
DeliveryMethod = EMAIL_DELIVERY_METHOD,
UseDefaultCredentials = EMAIL_DEFAULT_CREDENTIALS,
Credentials = new NetworkCredential(fromAddress.Address, EMAIL_PASS,EMAIL_HOST)
};
using (var message = new MailMessage(fromAddress, toAddress) {
Subject = subject,
Body = body,
Priority = MailPriority.High
}) {
smtp.Send(message);
}
}
I have enabled Less Secure Sign-in, and the configuration seems to be fine. What is the problem?
Try to remove the UseDefaultCredentials property.
If that doesn't work, set the properties individually (not using the object initialiser) and make sure Credentials is set after UseDefaultCredentials
see c# SmtpClient class not able to send email using gmail
I know this answere is a bit late, but You are using a NOT SECURE WAY to login to your gmail. Gmail actually throws an error but this is not send to you. You may receive an email that says something like:
Someone tried to connect to you gmail account from an unsecure
application
Or some similar. In this case you have to visit
https://www.google.com/settings/security/lesssecureapps
(Provided you are logged in)
and set this option to allow unsecure apps. Than you are allowed to send mails (even in this unsecure way).
Having the same problem atm but I dont want to allow unsecure apps, I want to change my code to be secure. But cant find anything that solves this.
Your code looks fine. Did you check that the email address hasn't been locked out? I.e. actually login to that email account on your browser. It happened to me before where the gmail account I was using got locked.
Related
I am using Asp.Net Core 3.1,And I am using default IEmailSender
interface provided from Microsoft send email, unfortunately it is
not working in server side after deploying
In my code, I tried to send the Email through localhost machine and it is working and sending the email perfectly then I deployed the system, but, when I need to send email through the application hosted in the server, sending email is not working, I mean the code is working and updating the information, but, the email not arriving.
This is the sample of EmailSender class that inherit from IEmailSender interface:
public EmailSender(string host, int port, bool enableSSL, string userName, string password)
{
this.host = host;
this.port = port;
this.enableSSL = enableSSL;
this.userName = userName;
this.password = password;
}
public Task SendEmailAsync(string email, string subject, string htmlMessage)
{
var client = new SmtpClient(host, port)
{
Credentials = new NetworkCredential(userName, password),
EnableSsl = enableSSL
};
// To avoid any error come from domain email server
ServicePointManager.ServerCertificateValidationCallback = delegate (object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) { return true; };
client.SendMailAsync(
new MailMessage(userName, email, subject, htmlMessage) { IsBodyHtml = true, Priority = MailPriority.High }
);
//client.Send(
// new MailMessage(userName, email, subject, htmlMessage) { IsBodyHtml = true }
// );
return Task.CompletedTask;
}
How can I allow sending email through the server, knowing that I checked the security in server end test sending email through the telnet and it is working fine.
As per Microsoft "System.Net.Mail" namespace is obsolete and they mentioned that you can use "MailKit" library instead.
You can read more from this link: https://learn.microsoft.com/en-us/dotnet/api/system.net.mail.smtpclient?view=netcore-3.1
After updating EmailSender to "MailKit", send email is working fine
and also more reliable in fact of the time.
I'm experiencing a weird problem, as the title says whenever I try to send a mail, the following exception is thrown:
System.Net.Mail.SmtpException: 'The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at'
Nothing out of the ordinary, however this is a code that was written about 2 years ago and hasn't been touched since, today when I ran it - suddenly doesn't work.
public static Task SendEmailAsync(string email, string subject, string htmlMessage)
{
return Task.Run(() =>
{
using (var client = BuildClient())
{
var message = BuildMessage(email, subject, htmlMessage);
client.Send(message);
}
});
}
private static SmtpClient BuildClient()
{
var smtp = new SmtpClient("smtp.gmail.com", 587)
{
EnableSsl = true,
UseDefaultCredentials = false,
Credentials = new NetworkCredential("xxxxx#abv.bg", "xxx")
};
return smtp;
}
private static MailMessage BuildMessage(string email, string subject, string htmlMessage)
{
var mailMessage = new MailMessage
{
From = new MailAddress("xxxx#abv.com"),
Subject = subject,
Body = htmlMessage
};
mailMessage.To.Add(email);
return mailMessage;
}
As you can see the host is gmail.com, but I'm using a different email provider abv.bg, I've also tried swapping that with a gmail account, but the error is still the same.
This is a somewhat shortened version of the original code, but this also produces the error, since im not using gmail, there is no such a thing as "Less secure apps", or 2fa, this cant be the cause and even if it was when I attempted to use a gmail account, I enabled the less secure apps option, to no avail. I've ran this code under both .net core 3.0 and .net framework 4.7.2, same results. I'm also running this completely locally, so time zones shouldn't be a problem. And I've tripled, quadrupled checked the password and email.
So I'm basically clueless to why this is happening, any tips would be appreciated.
i'm writing a C# email application which is currently being designed for use with Gmail so I can test authentication. However I'm getting an error which doesn't seem to make much sense as I am setting SSL to true and using a user and password.
Error Message:
System.Net.Mail.SmtpException: 'The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at'
using System;
using System.Net;
using System.Net.Mail;
namespace EmailSendingProgram
{
public class EmailSendingClass
{
public static void Main(string[] args)
{
Console.WriteLine("Type your Gmail Address: ");
string from = Console.ReadLine();
Console.WriteLine("Type your Gmail Password: ");
string password = Console.ReadLine();
Console.WriteLine("Type the Email Address you wish to send to: ");
string to = Console.ReadLine();
Console.WriteLine("Type the Subject of the email: ");
string subject = Console.ReadLine();
Console.WriteLine("Type or paste in your email (either text or HTML): ");
string body = Console.ReadLine();
EmailSendingClass email = new EmailSendingClass();
email.Send(from, password, to, subject, body);
}
/// handles sending the email
/// hardcoded to work with gmail just change the CreateSmtpClient from
/// "smtp.gmail.com", 587 to whatever you want to use
public void Send(string from, string password, string to, string subject, string body)
{
var message = CreateMailMessage(from, to, subject, body);
// Host and Port setup for use with Gmail
using (SmtpClient client = CreateSmtpClient("smtp.gmail.com", 587, from, password))
{
client.Send(message);
}
}
/// Defines the SmtpClient for the mail message
/// setups up the network credentials to send the email
private SmtpClient CreateSmtpClient(string host, int port, string from, string password)
{
SmtpClient client = null;
client = new SmtpClient()
{
Host = host,
Port = port,
EnableSsl = true,
Credentials = new NetworkCredential(from, password)
};
return client;
}
/// defines what is contained in the email and where it will be sent
/// also makes all messages send as HTML
private MailMessage CreateMailMessage(string from, string to, string subject, string body)
{
MailMessage message = null;
message = new MailMessage(from, to)
{
Subject = subject,
Body = body
};
message.IsBodyHtml = true;
return message;
}
}
}
I understand that something is being done incorrectly with the authentication but I can't seem to figure out what specifically. So any help would be appreciated.
I encountered a similar problem caused by TLS 1.2 support issues. If this is your case, the simplest solution might be to target .NET 4.6.1 or higher. Other suggestions can be found here and here.
The issue wasn't the program but rather was Gmail refusing sign in from "less secure apps"
I simply clicked the secure your account button and allowed this account to be signed in from less secure apps.
I'm using SmptClient to send email from a gmail account. This account sends lots of emails every day (sort of a support#mydomain.com automatic emails)
All was working fine until it suddenly stopped working. I didn't change anything in my application nor did i deploy a new version.
When i try a regular SmptClient example code it gives me this error message:
Unable to read data from the transport connection: net_io_connectionclosed.
If i change only the fromAddress and fromPassword to a different account, without changing anything else in the code, the code works!
Here's the sample code which i'm using: (The code if fine becuase it does work for a different account)
var fromAddress = new MailAddress("****", "****");
var toAddress = new MailAddress("****", "****");
const string fromPassword = "****";
const string subject = "testing... ";
const string body = "body test";
var smtp = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Credentials = new NetworkCredential(fromAddress.Address, fromPassword),
Timeout = 20000
};
var message = new MailMessage(fromAddress, toAddress)
{
Subject = subject,
Body = body
};
smtp.Send(message);
When i connect to gmail using the invalid account and send an email, it does work.
It seems as if the SMTP server is failing to authenticate.
I connected to the list of Gmail Latest Account Activity and it didn't show the connection attempts i made from code. Please help, Thanks!
I'm trying to send email with my website's address from a C# application.
This worked fine for several months until recently. (maybe my provider changes some things or someone else changed settings)
Here's the code:
private void sendEmail(Email invite) {
MailMessage mail = new MailMessage();
SmtpClient SmtpServer = new SmtpClient(smtpServerName);
mail.From = new MailAddress(emailUsername);
mail.To.Add(invite.RecipientEmail);
mail.Subject = invite.MessageSubject;
mail.Body = invite.MessageBody;
SmtpServer.UseDefaultCredentials = false;
SmtpServer.Port = 587;
SmtpServer.Credentials = new System.Net.NetworkCredential(emailUsername, emailPassword);
// SmtpServer.EnableSsl = true;
SmtpServer.Send(mail);
}
Here's the error:
The SMTP server requires a secure connection or the client was not authenticated. The server response was: SMTP authentication is required.
Looking at other questions I tried what they suggested, to make SmtpServer.EnableSsl = true. This didn't work at all. It gave the following:
System.Net.Mail.SmtpException: Server does not support secure connections.
I'm guessing I should disable SSL and have it the way it was before.
Any suggestions how to make email sending work again?
EDIT
I've tried without SmtpServer.UseDefaultCredentials = false;
I've tried with it set to true: SmtpServer.UseDefaultCredentials =true;
I've tried commenting that line along with the following //SmtpServer.Credentials = new System.Net.NetworkCredential(emailUsername, emailPassword);
That error message is typically caused by one of the following:
Incorrect connection settings, such as the wrong port specified for the secured or non-secured connection
Incorrect credentials. I would verify the username and password combination, to make sure the credentials are correct.
If you are sure that your Username and Password are correct, but you still get errors then it means that Gmail has blocked your application. Allow less secure apps in your Google Account settings
Visit this link to your Google Account settings for Less Secure App access.
Select your Google Account from which you are sending the mail.
Set Allow less secure apps to ON.
I think you have to set DeliveryMethod = SmtpDeliveryMethod.Network
this one is currently working in my PC, just i checked,working nice,try this
using System.Net;
using System.Net.Mail;
var fromAddress = new MailAddress("from#gmail.com", "From Name");
var toAddress = new MailAddress("to#example.com", "To Name");
const string fromPassword = "fromPassword";
const string subject = "Subject";
const string body = "Body";
var smtp = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
};
using (var message = new MailMessage(fromAddress, toAddress)
{
Subject = subject,
Body = body
})
{
smtp.Send(message);
}
You need to create an app password so that your application can bypass 2FA:
Sign in with App Passwords
Google App Password
If you are deploying the application on a server, try logging in your google account in your server. Bizarre thing is, smtp email sending app works fine in my desktop. Not in the server. This might be affected by how google's security mechanism works.