Q: Cannot set APN for personal hotspot, the APN is cleared automatically after I set it.

Hello Mtshali,

Thank you for using Apple Support Communities.

For more information, take a look at:

iOS: Troubleshooting Personal Hotspot

http://support.apple.com/kb/TS2756

1. Turn Personal Hotspot off and on: Tap Settings > Personal Hotspot or Settings > Cellular > Personal Hotspot.
2. Install the latest version of iOS.
3. Reset your network settings: Tap Settings > General > Reset > Reset Network Settings.
4. If you still see the issue, restore the iPhone.

Have a nice day,

Mario