How to troublehoot Teams Desktop App?

DLX 1 Reputation point
2020-10-26T17:06:58.513+00:00

Hi,

I'm having difficulties with MS Teams Screen sharing not working when initiated from the Desktop Application. The session starts, but only displays a black page with the users image displayed in the center.

I have since discovered that we can work around this issue by reversing the screenshare after it fails:

  1. User A: From Desktop App --> Chat to User B --> Share Screen --> Screen #1
  2. User B: Accepts the screen share. This fails to connect, leaving a black/grey screen with User A's icon onscreen
  3. User B: From this failed window, if they then press the 'Screen Sharing' then the screen share works.

I Have also found that if I create a 'New Teams Meeting' from within outlook, then the screen sharing works without issue.

All users and machines are effected on our Domain, with the issue starting ~6 weeks ago. Before that screen sharing from the desktop application worked fine.

To be clear, these are all internal users connecting to other internal users, all running on Windows 10 (1909 / 2004 / 20H2) Virtual Machines.

Has anyone seen anything similar, or have any advice on how to start troubleshooting this issue?

Microsoft Teams
Microsoft Teams
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  1. Sharon Zhao-MSFT 25,056 Reputation points Microsoft Vendor
    2020-10-27T06:40:19.047+00:00

    @DLX ,

    What changes do you do before this issue happened?

    You could check the health status of Microsoft Teams in Office 365 admin center > Health > Service health.

    Meanwhile, check if the ports UDP 3478-3481 and TCP 443 are open on firewall.

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