Huawei P9 Lite - After inserting the headphones / trying to talk, the phone turn

Hello
As in the subject.
I have a Huawei P9 Lite phone. For some time, after inserting the headphones and turning on the music, or when trying to answer / call, the phone turns off. Factory reset didn't help.
My guess is that the headphone socket and the loudspeaker for calls have a common power amplifier, which has failed, and can give DC voltage at the output.
It happened when I was listening to music through the headphones, suddenly something popped in the headphones (as if the constant voltage on the speakers) and the phone turned off.
The headphones are good.
Can my diagnosis about a power amplifier be correct?
How much money can the service charge for the replacement?

Best regards,
Charles

Did you clean the nest itself?

Hello
Of course, I cleaned the nest itself.
The speaker for calls is ok, it has 30 Ohm.
Charles

I would be more of a short circuit in the socket itself.

Hello
The short circuit in the socket itself is eliminated.
After disconnecting the socket, the telephone behaves the same.
In addition, I measured the socket itself - after disconnecting it from the electronics, I put an empty jack plug into it (only the plug without a cable) and checked that there was no short circuit between the ground and both channels.
Disconnecting the call loudspeaker also has no effect.
I do not know much about GSM servicing, but my task is probably cheaper / faster / easier to replace the entire motherboard than to combine something with a (most likely) damaged power amplifier ...
If anyone has other suggestions, I'm open, I know electronics a bit.

Best regards,
Charles

Start with a pure software as someone mentioned.