Visual Voicemail

Have you contacted Apple? Visual Voicemail on Apple devices is a feature of Apple and iPhone. If it's not working it's a defect of the phone.

( AT&T allows download a visual voicemail to any compatible device. Transcription is provided on Apple and Google devices and is a feature of Apple and Google. Samsung does not provide transcription)

If you Google the problem there are suggestions that Siri has something to do with the problem.

Other suggestions

https://itoolab.com/fix/iphone-visual-voicemail-not-working/#:~:text=Check%20out%20the%20instructions%20below,passcode%20to%20authorize%20the%20resetting.

I've actually switched the voice line not receiving visual voicemails to another device (iPhone 11 Pro) and visual voicemail didn't work on the second device either. I moved a different voice line (with working visual voicemail) to the iPhone 14 Plus that is having issues and visual voicemail worked. This leads me to believe the issue is with the line and not the device since I've tested with two different lines on the same device and it worked for one and not the other; and the defective line did not work on a device proven to work with visual voicemail.

For the sake of verifying all potential issues, I did also go to an Apple store and they told me this was a carrier issue and I've been on the phone with AT&T several times to reprovision the voicemail box.

I will test the link you sent with the iTooLab FixGo. Thanks for the suggestion. I'm open to any other suggestions anyone else may have as well! This phone is for my mother who is not the most technical person and having the ability to view her voicemails would help wonders with her missed medical calls.

Thanks!

Was the phone that was replaced capable of receiving visual voicemail?  It could be line was not provisioned for visual voicemail. If so need to call customer service to have problem corrected.