I've tried everything but for at least a year now my iphone (bought new in late 2022) has delayed voicemail notifications -- hours and sometimes days and weeks after a call came in. It's a huge problem and nothing (restarts, updates, toggling settings) seems to help.
You will only receive voicemails if you are connected to your carrier’s cellular network and you have Cellular Data turned on. Voicemail syncs using cellular data, because your carrier’s voicemail server knows nothing about your Wi-Fi connection.
If this is not the problem you need to contact your carrier for assistance, as voicemail is under their control.
Several Hours Delay Between Calls and Voicemails
