Personal hotspot is not working, then make sure that you enable tethering is enabled. Try different connection methods and make you iPhone available to connect all contacts. Turn off and turn on personal hotspot and reset network settings to make your hotspot not working on iPhone 11, 12 to connect successfully.
Fix Personal hotspot not working on iPhone 11, 12:
Refresh Airplane mode
Launch settings app on your iPhone.
Turn on “airplane mode” .
Restart your iPhone.
Then turn off “ airplane mode” .
Tap “ cellular” and make sure that cellular data is turned on.
Then tap “personal hotspot” and turn it on.
Now check whether personal hotspot is working or not.
Reset Network Settings
Open settings app on your iPhone.
Scroll down to “ general” and tap it.
Scroll down to “reset ” and tap it.
Tap “ reset network settings” .
Enter your passcode .
Select ” reset network settings” in the pop-up box to conform .
Wait until the process finished.
Then launch settings app on .
Tap “ cellular” and turned it on.
Then tap “ personal hotspot” and turn it on.
Now check whether personal hotspot is working or not.