I tried the old web based Message+ this morning, same results as the new one from the M$ store.  This is beyond unbelievable that an app that has worked properly for years, wasn't recently updated, has quit working.

This leads me to believe it is Microsoft problem, maybe Defender.

Strange you can send messagesfrom PC's but can't receive anymore...

Later today when I have time I am going to disable/suspend Defender after uninstalling both messeger apps, then re-install and see if that makes any difference.

It will get fixed sooner or later, there has to be a bevy of Verizon employees that have the same problem,  I am sure they are working on it (fingers crossed)...