I cannot set up voicemail on iPhone 7 Plus
I cannot set up voicemail on iPhone 7 Plus when I go to the voicemail screen it does not give me the option of setting anything up. When I try to call my voicemail, I get a message from AT&T saying I need to enter my mailbox number. I don’t know what my mailbox number is. I tried entering my phone number but that is not it. What’s going on here? Attached is a screenshot of my voicemail screen.
iPhone 7 Plus, iOS 12