Unable to send mail through G Suite from a Plesk server on Google Cloud: Invalid credentials for relay




  • Avatar
    Brian Chin

    I have been struggling with this one and was sure G Suite config was correct. Got  550, "5.7.0" error.

    You can check error codes here: https://support.google.com/a/answer/3726730?hl=en

    Solution 1: add another domain to "Add a domain or a domain alias" and verify it.
    Only that domain will be able to send mail.

    Solution 2: Change the full hostname in plesk (server settings) to a known domain in G Suite
    All domains will be able to send mail.

    Test it from the shell: echo TEST MESSAGE BODY | mail -s test mail subject youremail@yourdomain.com

    PS: in /etc/postfix/main.cf I only modified this line: relayhost = [smtp-relay.gmail.com]:587

    Just wanted to share what worked for me.

    Comment actions Permalink
  • Avatar
    Lev Iurev

    Hi @Brian Chin Thank you for sharing!

    Comment actions Permalink

Please sign in to leave a comment.

Have more questions? Submit a request