impossible to pick up calls teams

Hello

Recurring problems with Teams telephony: when they receive a call from outside, they often can't pick it up, and when they do, it hangs up or tells them they're already on another call. I've tried system updates, HP updates, uninstalling all Teams on the PCs and reinstalling the latest version, cleared the Teams cache, system cleanup, the problem persists.

Has anyone had this problem before? 

Thanks