Microsoft 365 OAuth App Settings


This is an odd one,

Does anyone know, i need to have specific ports open for inbound to allow Microsoft 365 OAuth App to work ?

I am getting the following error on the server
Can’t use Channel::Driver::Imap: #<Net::IMAP::NoResponseError: AUTHENTICATE failed.>

I cant seem to find a doc that says we need say port 993 inbound open for this to work.

Overall, when i try to authenticate it works fine and everything works without a problem, but in 30 minutes or so, I need to re-authenticate the email account.

Thanks for your help

Smells like your token is expring for some reason.
I’m afraid I can’t help further without knowing exact versions or even better without having the template for technical assistance.

Any way. The tokens have to be refreshed within 60 minutes other wise they’re getting invalid. Usually this shouldn’t be of an issue because Zammad does keep it updated or even updates it if the instance was offline longer than that time.

Ensure that your installation is allowed to use HTTPs to Microsoft (so to the outside).
Your production.log may indicate further information.


  • Used Zammad version: Zammad version 5.0.x
  • Used Zammad installation type: package
  • Operating system: Debian 10
  • Browser + version: Chrome

Expected behavior:

  • Setup - Microsoft 365 Channels and sign in with one email and get it linked to an office 365 mailbox

Actual behavior:

  • Every few hours (trying to understand if its time-out on the account)
    there is an error on the inbound side - imap: #<Net::IMAP::NoResponseError: AUTHENTICATE failed.>

Once I re-authenticate, everything works as expected/

Steps to reproduce the behavior:

  • just occurs every few hours.

Could you look up that error message in the production.log and share one complete traceback from it?
Ensure that your Zammad instance can communicate with the internet without any trouble (especially via HTTPs) to Microsoft. Port 443 is needed for token renewal which could explain why the issue comes back after some time.

I’m afraid I can’t reproduce this on local environments - SaaS doesn’t seem to be affected as well.

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