503 This mail server requires authentication when attempting to send to a non-local e

[bartabc]

When i sent a email to any domain on my plesk windows servers i receive this message:

503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.

Nothing is change, this error start and i try use reconfigurator plesk installation but does not fix this issue.

How to fix this ?

 

[Darko Bazulj]

check relaying options under mail settings.
If relay isn't disabled you probably need to use SMTPAuth or POP before SMTP to send mail to external domains via your mail server. Or enable relay from some locations.

 

[bartabc]

Just run this command to fix this:

mchk.exe --all --fix=all

This solve my problem.