Wondering what the Com.Android.Server.Telecom framework is? It is the built-in feature responsible for routing and managing your calls. Considering how useful it is, you can imagine how much of a headache it would be if it stopped working.
Unfortunately, I’ve experienced this first-hand. I couldn't make calls on my Galaxy S21 because the telecom service kept glitching. But I knew a couple of tricks that got it up and running again.