Can't Connect to Voice Mailbox error 9004

[stindall94]

When I am at home, on wifi only with cellular data turned off, I can't listen to my voicemails.

I get the alert "Can't connect to your voice mailbox" that tells me to call customer service and give them the error code 9004.

When I turn off wifi and turn on data, the visual voicemail feature lets me listen to my voicemails, but won't transcribe any of them for me to read.

Is there a way to get it to transcribe my voicemails, and is there a way to do this on wifi or is cellular data needed? If so, why?

[deloused]

That should work if WiFi calling is active on the phone