- Go to Settings-> Cellular-> Cellular Data-> then hit the switch to turn it off to turn cellular service on or off. Wait a few seconds before tapping the switch to reactivate cellular data. Check to check if visual voicemail is working again after restarting your iPhone.
- If you want to test out the Airplane mode technique, go to Settings-> Airplane mode and toggle it on. Restart your iPhone after 30 seconds or 1 minute.
Then test whether the visible voicemail feature on your iPhone is fixed.