We are experiencing an issue where incoming calls from external users intermittently do not have audio. We cannot hear the caller and the caller can't hear us. This has been happening for more than a week now. Teams to teams internal calls work fine, and outgoing calls have no issue. We are set up with Direct Routing through our vendor, Allstream/Zayo, who is hosting the SBCs. Again, maybe about 50% of the incoming calls are fine, where the other half seem to have dead air. If the user calls back after it fails, the call connects fine. This is not network related, since we can replicate this issue with laptops on the business network, laptops not on the business network, Teams on mobile devices connected to mobile networks. We have opened a ticket with both Allstream/Zayo and Microsoft to troubleshoot. Our provider looked into the issue and said that calls are routing fine and handing off to Microsoft ok, and that it appears to be a MS issue. Microsoft support is slow to respond, or calls back at odd times, so trying to troubleshoot is a hit or miss.
