StrMca: I think you miss the point of my post.

On the same computer, one the same IP session with my router (i.e. there are no computer restarts and the network remains connected), one of my Google Gmail accounts shows the call button, but all calls fail. Calls used to work on this account and now don't complete.  I log off that account and on to another Gmail account and calls go through fine.

Therefore:
1. I have the Call Icon on both accounts,
2. Since it works on one account, the proper ports are open.

Please advise what is operation of Google Call on the working account that no longer works, when the Call Icon does appear and other instances of Google Call work.  In my mind, this is a Google Account issue.