Cellular callers get a busy signal or my T-Mobile voicemail when calling my forwarded AT&T landline number. Started in December 2018. AT&T said they have checked everything including my C.O. equipment. T-Mobile can't find an issue.
I can forward my AT&T landline number to any other phone on my account or any other cellular company number, and there is no issue.
Cellular callers only get a busy or Vm when calling my home and it's transferred to my cell.
The callers are calling from a cell phone. If they call from a landline, I will get the call.
I have opened several tickets, but T-Mobile keeps closing them assuming the issue is resolved.
Any suggestions. If you call from a landline to my landline, I get the call If you call from a cell to my landline, you will get a busy or VM.