The issue has been resolved.
Action Required
If you disabled the Teams Plug-in in Control (under Security Policies or Protocol Policies), re-enable it.
If you advised end-users to disable it in the Windows Client, advise them to re-enable it.
Otherwise, no action is required. Control instructs the Client to update to the correct Teams components automatically.
Root Cause
Previously, the Microsoft components of the Teams Plug-in would update on the Client device automatically, possibly before being tested by Workspot.
A recent update from Microsoft proved to be incompatible with the Teams Plug-in and resulted in connection failures.
Solution
Workspot now ensures that the Client device uses the latest known-good versions of these components.