I can't check my voicemail on my Apple iPhone 15 iOS 17
Cause 4 of 4: You're trying to check your voice messages when abroad
The default voicemail number can only be used if you're calling form your home network.
Solution: Call +447836121121 and key in your 4-digit PIN to check your voice messages when abroad. Please note that you need to set a PIN before you can check your voice messages when abroad.
