If your iPhone says 'Voicemail Unavailable' when trying to change the password, it might be a network issue or something with your carrier. Try these fixes:
1️⃣ Check your signal – Voicemail needs a good connection. Try turning Airplane Mode on and off.
2️⃣ Restart your iPhone – A simple restart can fix a lot of small issues.
3️⃣ Reset Network Settings – Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings (this won’t delete your data).
4️⃣ Contact your carrier – Some carriers require you to change the voicemail password through their app or customer service.
If none of these work, your carrier should be able to help. Hope this helps! 😊