The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated
I am sending mail from remote machine to my machine using the server name provided by remote user. i am getting following error "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated".
I am doing this through C# code .
Do think twice before you allow anonymous connections on the internet.
You will be a subject to spamming the outside world, and thereby be listed and blocked within hours/days.
Best thing is to simply provide a username and password as it asks for.
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There is difference between open relay and anonymous connection, which is required for authoritative domains so other servers can deliver mail to your authoritative domains.
In this case, it looks like you are trying to send email using mail server that is not authoritative for recipients domain, so it is considered relaying. If you provide username and password, then it is not open relay and mail is processed.
- Edited by Tonza Sunday, September 04, 2011 5:09 PM