SMTP server response: 503 This mail server requires authentication

mohammed-rizwan

I'm using OsAuth2 with office365 mailbox. Till it was working fine but since last one month I'm getting below error:

Unable to email via PHP mail function Unable to send mail: mail(): SMTP server response: 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.

When I send email manually from "Test Outgoing Email' it works fine. But when I send email via filter it's not working.

Appreciate it if someone help me to troubleshoot this issue.

KevinTheJedi

mohammed-rizwan

The error is pretty clear. It’s saying the email you are using to send mail is not using authentication which is required to send to external addresses. Please reach out to your hosting provider and/or mail provider for further assistance.

Cheers.

mohammed-rizwan

Yes, I do understand that server requires authentication but I set the outgoing (SMTP) authentication to "Same as Remote Mailbox" which was working fine till couple of weeks ago and now I'm getting this message. Is there any change I have to make it order to allow authentication. Note that I'm using oAuth2. Thanks

KevinTheJedi

mohammed-rizwan

What's the SMTP information you are using?

Cheers.

mohammed-rizwan

hostname: smtp.office365.com
Port: 587
Authentication : Same as Remote Mailbox

KevinTheJedi

mohammed-rizwan

I'm not seeing much else online for this particular error other than a firewall issue, wrong login information used, etc. At this point i'd recommend reaching out to your mail administrator and/or mail provider for further assistance. This doesn't appear to be an osTicket issue as this error is coming directly from the mailserver itself.

Cheers.

mohammed-rizwan

Can you please confirm below OAuth2 Authorization settings:

Thanks

KevinTheJedi

mohammed-rizwan

Yea, you changed it which is why it’s not working. Please go back to the default Scopes (offline_access https://outlook.office.com/Mail.ReadWrite), delete the existing token, re-authorize to get a new token, and retest.

Cheers.