I live in an apt building with a call box that allows me to remotely let visitors into the building. Visitors find my name on a directory, press call and it is supposed to ring my phone. Instead the call goes directly to my voicemail. It never rings my phone or shows as a missed call. I have an Iphone 11 Pro Max.
It looks like this is a continuing problem with Tmobile as I have seen similar posts from 4 yrs ago. I added the call number to my contacts and turned off LTE as others suggested, but it still does not work.