Teams Incoming Call Issue

Copper Contributor

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.

3 Replies



We are having a very similar issue to you - which started on 10th April.

We have one-way audio/silent calls which has affected our business to the point where we have had to initiate our BCP plan.

We use Teams Direct Routing with Gamma, who also have run traces on the call traffic.  It looks like the issue is after the SBC on Microsofts end.  We too have tickets open with Gamma and Microsoft.

18 days and counting......

Here's hoping it's sorted soon.


@Emma_Skeith Looks like another Gamma to Teams user posted with the same issue (with another confirming report in the comments), arising from the same time. Per the post, the company correct this by switching from Direct Routing to Operator Connect, which unfortunately we cannot do at this time. Hoping MS can sort this out sooner than later. At least I find solace in knowing this is not an issue on just my end.

@SBFKevin Thanks for your reply - I will look into Operator Connect.

Hope you are sorted soon :)