Meetings disconnect after 5 seconds when joining EVERYTIME.

I am the teams admin over the computer I worked. I've had multiple instances where the end user is having issues with Team meetings disconnecting. Direct calls, One on one, work fine.

When they try to join scheduled meetings, it joins and drops them after about 5-10 seconds EVERYTIME. I can test that by creating a meeting with just me, starting it and inviting them in. I see them join and there portrait for about 5 seconds then they drop. Need assistance. I have tried them at the local office which has 3 floors each with about 50 people not having this issue as well as them at home on there internet with NO VPN connection.