Bafang 8fun rear hub

When turning the crankarms the hub motor starts. The problem is I have not even turned
The display (c961 display) on yet.
I cannot turn the display on when pressing the powers Button. If I unplug and plug in the display I can turn it on and it works like It should. If I turn the display off the hub motor stil works which it should not. Has tested it with 2 other wheels and they work fine, so the problem is in the rear hub.

Please help me

First, what happened just before it stopped working?

Next, is the controller inside the rear hub? Or is it separate?

If it's in the hub, then the controller has failed, and would need to be replaced.

If it's separate, then something else in the hub has failed, either hall sensors or speed sensor, most likely, but it could just be damaged wiring.

Wiring can be damaged at the axle exit, from bending or crashes, or other issues.