Huawei Mate 9 WLAN problems?

I've already tried everything and I'm at a loss. If I want to do the WLAN on my Huawei Mate 9, it deactivates itself. Rarely does it work 1 to 2 weeks as long as I do not exhibit it. Sometimes sometimes it does not connect for weeks. Reset to factory settings, I tried, it was a short time after the same problem. I've tried everything imaginable but can't find a solution. Let alone a reason that it sometimes works for a few days and then months.

It is broken.

One chicken. It has an antenna problem.