Mysterious setting reset and hotspot problem

Hey everyone!

Hopefully you can help me with a little problem:

My Huawei P9 fell. Now, no device can connect to its hotspot - two laptops and a phone say "Connection not possible", another phone falsely claimed "Invalid password entered" (and when i removed the password from the hotspot the error message switched to "Connection not possible" as well). The day before the fall hotspots were working just fine.

Also, each time I restarted the phone some settings were mysteriously reset. First I see a pop-up message reading "Some applications require data connection. We recommend hiring a data plan." - even though my provider is being recognized and I have working mobile data. Then, after every restart the 24-h-clock format, the percentage display of the battery, the auto-rotate and a lock-screen setting are reset to default. One time, I changed the SSID of the hotspot and after the reset it was just changed back to default.

After I took out the SIM, I tested if the settings reset happens without SIM. It did not. After that it did not occur again with inserted SIM card, neither. However, the "You should get a data plan" pop-up still happens and the hotspot still doesn't work.

How can I fix this problem, or more specifically, make the hotspot work again? I have tried a bit with different APNs, but to no avail. I also did a network setting reset.

I am not even sure if the issue has to do with software or hardware.

Any help is very much appreciated, thank you! :)

Kind regards