I had a painful trouble with my iPhone, since several days ago my friend cannot connect to my Personal Hotspot. I was using iPhone 7 Plus with iOS 12.4 and Telkomsel cellular network.
Many solutions that i had ever tried such as Reset Network Setting, Restart iPhone and Updating iOS version but still didn’t solving my problem.
So i decided to search on Twitter and finally i found this.
1. Go to Settings > Cellular > Cellular Data Network
2. Scroll down on Personal Hotspot section
3. Fill the blank with this setting:
APN : internet
4. Blank the username and password
See this example below
Finally, other devices successfully connected to my iPhone Personal Hotspot.
I hope it works on your device :)