Other reasons include problems with VoLTE settings, an old iOS version, or issues caused by Wi-Fi Calling.
1. Change VOLTE or Data Only Setting
If your carrier supports it, your iPhone can use LTE for data only or VOLTE for both voice and data. Sometimes, weak signal strength causes issues with VOLTE. Selecting the LTE “Data Only” option may resolve your problem.
2. Turn On and Off Airplane Mode
A temporary network glitch could be causing the problem. Turning Airplane Mode on and off refreshes your device’s network connections.
3. Check Wi-Fi Calling
Wi-Fi Calling lets you send and receive calls over a Wi-Fi network instead of your cellular connection. For some users, turning this feature on or off fixes the error.
4. Make Sure Caller ID Is Enabled
Caller ID makes sure your number shows up when you call someone. If this is turned off, especially if you travel and use SIMs from other countries, it can cause call errors.
5. Turn Off Dial Assist
The Dial Assist feature automatically adds international or local prefixes when you dial a number, but sometimes it gets it wrong. Turning this feature off may help.
6. Set Correct Date and Time
Incorrect date and time settings may cause issues. You should also enable location-based Time Zone updates.
7. Log Out of the Digits App (T-Mobile Users Only)
If you use T-Mobile’s Digits app to handle multiple numbers, sometimes it can interfere with phone functions. Logging out may stop the error.
8. Reset Network Settings
Your iPhone’s network settings control how it connects to mobile and Wi-Fi networks. Incorrect settings may cause failed calls. Resetting these settings puts them back to default, but you’ll need to reconnect to Wi-Fi networks and re-enter passwords.
9. Update iOS to the Latest Version
Keeping your iPhone’s iOS up to date helps avoid bugs and glitches that cause call problems.
10. Restore iPhone to Factory Settings
If none of the above steps help, your iOS system may be deeply corrupted. Restoring your iPhone to factory settings can fix the issue, but this will erase everything from your device, so backup is important. If you’re still having problems, you can also try using headphones for calls, as this has helped some users. However, the real issue might be a hardware problem. If so, you may need to consider a replacement, especially if your device is under warranty or you have insurance. Bring screenshots of the call failed error with you if you visit an Apple store.
