If you are experiencing issues related to call quality or routing on Teams, the below steps can be used to check the call stats in the Teams portal to help determine the cause.
To access the Teams portal in Office365
Log in to Office365 as normal, you should see Admin:
Selecting admin will take you into the admin section for your Office365 account. From here you can see all the services you have, including Teams.
To see high-level Interconnectivity VIA trunk quality stats
Select Voice, Direct Routing. You should see a long string of numbers/letters as shown below. Select this to display various trunk quality stats.
To see individual call stats
Select Users, and click on the user who has reported call quality problems.
Go into call history.
Select the call you experienced issues with.
On the screen that opens you will see some high-level stats for the call:
Click on advanced and you will see more detailed stats about the call: