Hi @OLB. I guess you need to add your certificate in Zammad: click
If this is the official “outlook.office.com” endpoint failing with a self signed certificate error, I’d have serious questions. Make sure you have no application aware firewall that plays man in the middle replacing certificates.
Thanks for your reply, but my certificate is installed:
Thanks for the feedback, we have a Firewall (sophos) but it delivers the same certificate.
The main question is: What happened on 27th of January? You wrote that it worked before, so I guess the issue is in the environment, not in Zammad.
Maybe, we have autoupdate for Ubuntu. This makes me wonder: “certificate verify failed (self signed certificate in certificate chain)”
outlook.office.com is not part of your certificate chain and thus you cannot install an certificate for it. If you did, this might be the root of the issue. Just might.