Voicemail Error Message on iPhone XR


I just became a Visible customer.  Porting went well, but I keep getting the following message after entering a password to set up voicemail: "Voicemail unavailable.  Could not authorize access." I've tried this numerous times and get the same message. I've waited patiently in line to chat with an agent, and both times I've been kicked off, the last time I started out at 38 and got to 8 before it happened.  If anyone has any suggestions, I'd appreciate it.  I don't know if this detail will help, but when I go to Settings>Phone>my cell number is listed as the temp number issued when I was switching carriers.  Thank you in advance!