This question already has answers here:
Modern Oauth2 authentication for sending mails using Nodemailer nodejs
(3 answers)
Closed 13 days ago.
I have to implement message sending via outlook account but every time I authenticate smtp client library throws an exception also I can mention that with imap client everything works fine.
535: 5.7.3 Authentication unsuccessful
My code:
private const string SmtpLink;
await base.SmtpClient.ConnectAsync(SmtpLink, 587, SecureSocketOptions.StartTls);
SaslMechanism oauth2;
const string authMechanism = "OAUTHBEARER";
if (base.SmtpClient.AuthenticationMechanisms.Contains(authMechanism))
oauth2 = new SaslMechanismOAuthBearer(account.Email, credentials.AccessToken);
else
oauth2 = new SaslMechanismOAuth2(account.Email, credentials.AccessToken);
await base.SmtpClient.AuthenticateAsync(oauth2);
I am using MailKit library. I have spent a lot of time for searching solution but nothing helped. Hope someone will help
Are you using a personal account? There's currently a problem with XOAUTH for personal accounts (hotmail.com, outlook.com).
Here are some details: https://learn.microsoft.com/en-us/answers/questions/1168272/oauth2-for-smtp-send-granting-accesstoken-but-retu
Related
I am trying to send an e-mail using c# MailKit SMTP (code below).
It connects successfully (with Connect method) and then it fails on Authenticate method call with an error " Username and Password not accepted.". I know the user name and password are correct. I also tried "mail.optusnet.com.au" server on port 25 - same story.
What is wrong with my call to smtp.Connect method. I have spent whole day experimenting and got nowhere. Can somebody help please.
// send email
using var smtp = new SmtpClient();
smtp.Connect("smtp.gmail.com", 587, SecureSocketOptions.StartTls);
smtp.Authenticate("rejkid#gmail.com", "Password1");
smtp.Send(email);
smtp.Disconnect(true);
Google no longer allows your password to be used when authenticating via SMTP, POP3 or IMAP.
You either need to use OAuth2 or you need to enable 2FA on your Google account and then generate an app-specific password and use that.
The Exchange host that I am trying to send emails from does not require authentication. In the past I have successfully achieved this using SmtpClient Class, but as Microsoft is recommending Mailkit, I prefer going for this one.
Does Mailkit always require a username and a password to connect? I have been searching for an answer everywhere but I cannot seem to find one.
This is my code so far:
private void Send(MimeMessage message)
{
using (var client = new SmtpClient(new ProtocolLogger(Console.OpenStandardOutput())))
{
client.Connect(Host, Port, SecureSocketOptions.None);
client.Send(message);
client.Disconnect(true);
}
}
And of course I am getting an error: 5.7.1 client was not authenticated
Thank you loads.
Does Mailkit always require a username and a password to connect? I have been searching for an answer everywhere but I cannot seem to find one.
MailKit does not require authentication - that's up to the server to require it or not.
If a server doesn't require authentication, your code just needs to not call client.Authenticate() (or AuthenticateAsync if you are using async code) just like you attempted to do in your example code snippet.
5.7.1 client was not authenticated is an error that came from your SMTP server when you attempted to send a message and suggests that your SMTP server is configured to require authentication.
None of the exception messages that MailKit throws start with an error code string (5.7.1 is an SMTP error code), so if an exception is thrown starting with an SMTP error code string, then it means it came from the server.
We are thinking about moving to O365; however, we developed software that uses our current Exchange server to send email both to external users as well as to a support box when errors occur.
I've been testing this to ensure that the code we have in place will continue to work with O365 but so far, I have not been very successful.
I have tried using .Net's SmtpClient as well as MailKit's SmtpClient and neither one seems to work. I keep getting error (this is the error from MailKit -- the .Net error is similar)
"AuthenticationInvalidCredentials: 5.7.3 Authentication unsuccessful [*.prod.exchangelabs.com]"
I can use the credentials that I have in my code to log into OWA -- so I know the credentials are valid. Is it not possible to send email via O356? Is there any special configuration that has to happen in Exchange to make this possible?
Here is what I've tried so far:
MailKit
var msg = new MimeMessage();
msg.From.Add(new MailboxAddress("Support","support#mydomain.com"));
msg.To.Add(new MailboxAddress("Me","me#mydomain.com"));
msg.To.Add(new MailboxAddress("External User","euser#externaldomain.com"));
msg.Subject = "Test";
msg.Body = new TextPart("plain"){
Text = "Here is a message for you"
};
using(var client = new SmtpClient()){
client.ServerCertificateValidationCallback = (s,c,h,e) => true;
client.AuthenticationMechanisms.Remove("XOAUTH2"); //Not sure what this does. Have tried with and without
client.Connect("smtp.office365.com", 587, MailKit.Security.SecureSocketOptions.StartTls);
client.Authenticate(new NetworkCredential("support#mydomain.com", "supportPwd"));
client.Send(msg);
client.Disconnect(true);
}
The .Net SmtpClient code looked very similar to the MailKit code.
Is there a way to send through O365 with a licensed user? (code above)
Are there any special settings required in Exchange or on the licensed user to make this work? (If the answer to 1 is yes)
Is it possible to send email through a shared mailbox for which the credentialed user has Send As rights?
Update
I'm still getting the same error message. We do have MFA enabled for our domain users. However, we have a policy that does not require MFA for users when they are signing in from a trusted location (our org's IP). I also listed our IP as a Trusted IP. In my mind, MFA shouldn't be the issue here.
I know the credentials are correct. I copied them from the code and pasted them in to the login screen when signing into M365 -- and I got in just fine.
What am I doing wrong?
Yes, you can.
Usersettings:
Server-settings :
https://support.office.com/en-us/article/POP-IMAP-and-SMTP-settings-for-Outlook-com-d088b986-291d-42b8-9564-9c414e2aa040
SMTP server name smtp.office365.com
SMTP port 587
SMTP encryption method STARTTLS
No, you cannot. You need a licenced user to send mail via SMTP.
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_o365admin/set-up-smtp-relay-with-shared-mailbox/d7b98214-9564-432c-b098-525a98c529fb
A customer of ours has a newsletter system set up with TYPO3 and we had to create a new mailbox for this. However, a light one will suffice: instead of a Office 365 Business Premium we only assigned a Office 365 F1 licence.
Edit: also found this: Can Office365 shared mailbox use SMTP?
For anyone who is having similar issues, I found that my problem was a Conditional Access Policy. Microsoft provides a Baseline Policy: Block Legacy Authentication -- which had been turned on in our AAD.
In looking at the Policy, it is designed to BLOCK any authentication mechanisms that don't require MFA. This includes things like POP and SMTP. Once I disabled this policy, the code listed above worked just fine.
For me only disabling "Security defaults" helped.
This question already has answers here:
Testing SMTP server is running via C#
(5 answers)
Closed 9 years ago.
I had web application that users can set SMTP server information (server/host, SMTP Port, Username, Password, EmailAddress, usedSSL). i need when user set information validatre server without sending email and check Is smtp information valid or not?
I found website that works perfect and check is SMTP server alive (but not authentication check).. http://mxtoolbox.com/diagnostic.aspx
Edit 1:
Tanx #Dieter DHoker help me to find Testing SMTP server is running via C# in comments...
Is there anyway that i check authentication information (username & password & email address) as i need to check all smtp information is valid or not? that i asked before..
There's no username and password in SMTP (see rfc 821), so there's no way to test that.
You could use a MAIL FROM and RCPT TO sequence, but not send any DATA, to see if you'll be allowed to send mail with the given information, without sending an actual mail.
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
.NET SMTP Client - Client does not have permissions to send as this sender
I have an ASP.NET MVC3 application which performs the following code.
MailMessage message = new MailMessage("none#none.com", "none#none.com", "Test Message","Test Body");
EmailManager.Send(message);
I then have a referenced DLL which is used for sending emails.
public static class EmailManager
{
#region Public Methods
public static void Send(MailMessage message)
{
if (ApplicationConfiguration.Instance.EnableEmail)
{
var client = new SmtpClient(ApplicationConfiguration.Instance.SmtpAddress);
client.UseDefaultCredentials = true;
client.Send(message);
}
}
#endregion
}
The issue I have is that when I send the email I get the following error:
Mailbox unavailable.
The server response was: 5.7.1 Client does not have permissions to send as this sender
The interesting thing is that when I use the same code directly within my Web app, the email is sent correctly. Is there a reason why the credentials are not being picked up when being called via the referenced DLL? Possibly because it is static (or can credentials not be picked up outside of the web application?).
This usually happens when the SMTP server is locked down. It probably has a whitelist of IP addresses and your's isn't one of them, or your to address is not in the list of authorised outbound domains.