XOAUTH2 authentication mechanism not supported

sametyilmaznet

Hello,

I am using Microsoft Office 365 as the email provider. I have enabled the XOAUTH2 plugin on OsTicket and configured all the necessary settings on the Microsoft side.

I can successfully connect using IMAP and create tickets from incoming emails without any issues.

However, despite correctly configuring the outgoing SMTP settings, I am receiving the error "XOAUTH2 authentication mechanism not supported."

Is there anything extra I need to configure on the SMTP side? Many others are experiencing the same issue, but despite trying all possible solutions, I still haven’t been able to resolve it. Could this be a software-related problem?

sametyilmaznet

I am leaving the screenshots of my configuration below.

KevinTheJedi

sametyilmaznet

I cannot replicate this issue. Are you using a hosting provider? I suspect they are blocking traffic, etc. as your config looks entirely correct. Also, don’t reconfigure OAuth2 for SMTP if you’ve already configured for IMAP. In the SMTP tab set Authentication to “Same as remote mailbox” and it’ll reuse that information. If you still get issues contact your hosting provider as they are likely doing something with that traffic, etc.

Cheers.

sametyilmaznet

KevinTheJedi

Thank you for your response.

I am hosting on my own servers, and my server is a VPS. cPanel is running on AlmaLinux. I’m not experiencing any issues with SMTP authentication, and all the necessary components for OAuth are installed on my server. I don’t think the issue is related to the server itself.

Despite all of this, I have reviewed many things on the server, and there doesn’t seem to be anything wrong. Do you have any other suggestions?

sametyilmaznet

Hello,

I solved the issue for users who want to run OsTicket on servers with cPanel or any hosting control panel by disabling a security setting in the cPanel SMTP configuration that was blocking spam.

To disable the relevant setting:

Go to Home > Security Center > SMTP Restrictions and disable the SMTP restrictions.