Several users are reporting problems joining Teams meetings and making calls. Calls may fail to connect, audio may not work, or users may see a message saying, "Sorry, we couldn't connect you." The Microsoft 365 service health dashboard initially showed no incident. Is anyone else seeing this, and has Microsoft acknowledged the problem?
3 Answers
We dealt with similar Teams failures recently. Packet captures showed problems with UDP 443, which wasn’t allowed through our firewall. We also found that Teams’ required IP ranges and domains had changed since the original setup. Updating the endpoint allowlist and permitting UDP 443 resolved the issue for us.
Yes, we’re seeing the same thing. Calls are connecting without audio, and some attempts fail completely. Microsoft has since acknowledged it under service health incident TM1475580.
One of our users had two calls fail with the connection error while I watched the issue happen. Calling from my side produced the same result, and the call only worked when she switched to her mobile. So far, our affected users are mainly in France and Spain.
That’s worth checking for persistent or environment-specific problems, although this particular incident appears to be a broader Microsoft service outage.