My company has been successfully using the free version of Teams since the advent of Covid-19 and plan to move to 365 in the near future.
We have an issue with a few users at the moment whereby we can connect to our org via a web browser but cannot connect through the app. when we try it tells us that we do not have access to this org. the strange thing is that they can access guest orgs through the app but not our own.
I've gone round in circles trying find a solution and it's driving me up the wall.
@Stuart_Colburn Hey, have you tried to manually sign out and back in using the Teams desktop client at the affected users?
If that has already been done without success you can try to clear the Teams cache from this location AppData\Roaming\Microsoft\Teams (there are some guides out there being selective but just delete all the content in the Teams folder).
If no success, does a removal and reinstall make any difference?
I am attaching these suggestions at once just to avoid multiple replies with one solution in them. Let me know how it goes!