SMTP error: “Client does not have permission to submit mail to this server”

Question

I\'m getting the following error while sending email. What could be the cause?

Client does not have permission to submit mail to this server. The s

Answer 1

It appears you are using an SSL/TLS connection to send the mail message, however it appears for some reason that the code is sending the request to open the connection twice which is not valid. Hard to tell just from the exception and stack what the problem is. Post the sending code if possible.

Answer 2

Perhaps the SMTP server requires authentication (username / password) and you don't supply them? (Just a guess)