MS Teams Desktop Client not passing through Camera Video to other users

[Home2020]

Good Day, I have an issue with a user where their webcam works just fine but when she joins a meeting all you see is her profile picture on the other end instead of her Webcam video.

When I look on her computer both Videos streams (Mine and Hers) are playing so she didn't realize the other people were not seeing her video until they brought it up, plus when in the Teams device settings it shows at the bottom her video playing but just not passing through to the other participants in the meeting. Tried toggling the Video On and Off button but still nothing :( 

When using the Teams Web client, both Video Cams show to both parties so I'm not sure why it is only the Teams Desktop Client on her Windows 10 machine not showing the camera feed to the other participant.

Permissions in the client are all enabled for Camera, etc ...

Hoping someone has ran into this issue before. I have already uninstalled and reinstalled the desktop client to no avail. Thank you

[#2]

@Home2020 that's rather odd, perhaps her firewall is blocking the ports used by video for some reason? 3478-3481

[#3]

@Steven Collier Hi Steve, doing the test between her and I, we were on the same network so that makes it even odder :(

My video was coming through to her but hers not to me so same Firewall and Proxy.

It works for every one else so far on the same network plus as I mentioned, using Teams Web client on her machine works just fine. It doesn't make sense.

[#4]

@Home2020 I would imagine something in the devices network stack, for example the client firewall.

When you use the browser traffic is sent over https TCP port 80, the Teams desktop client will try to use UDP Port 3480 for Video.

[#5]

@Steven Collier Good Day, these are Domain managed computers so we would all have the same Windows firewall settings and the Network firewall is controlled by our domain Admins. So if UDP Port 3480 for Video needs to be open it would already be open as all other clients are working just fine. Does seem to be open though when I check. Looks like I'll just have to reimage her another laptop just because we can :) This is a weird one though. Even tried setting the Internal Camera driver as a USB Cam Driver from another post i read but still didn't work. If anyone else is reading this, the Laptop I am working with is a Lenovo ThinkPad X1 if that matters.

https://www.ipfingerprints.com/portscan.php

Host is up.

PORT     STATE    SERVICE

3480/tcp filtered plethora

https://www.ipvoid.com/udp-port-scan/

Port Type Status Service

3480

UDP

Open|filtered

plethora

[#6]

@Steven Collier Starting in the last 3 days , we've received reports that teaching staff can see their video image from the camera but their student's cannot see them.  This problem is specific to the Teams desktop app as the video works fine when using the browser version of Teams.  We've asked them to check for updates but most are running the latest version of Teams.  We are also running on Domain managed computers and all of them are the same make and model.  The firewall ports are not the problem so any other suggestion you could provide us would be greatly appreciated.

[#7]

These are the instructions to fix the issue with incoming videos . We Have to clear the Teams cache from the affected users machine.
1-Sign out on Teams > Quit Microsoft Teams by right clicking the icon and select Quit.
2-On your keyboard, Hold Windows key and Press R.
Cut and paste %appdata%\Microsoft\Teams in the RUN then OK.
3-Delete the contents of the entire folder.

If this does not fix the issue then we have to check the box for "Disable GPU hardware acceleration" in settings. We can go to settings by clicking on three dots next to our picture on teams main screen.

This will solve the issue.