Not able to switch Wifi on


I own my FP since X-Mas and everything was very well.
But now suddenly the Wifi turns off and I’m not abel to switch it on again.
When I try to do so, via Settings/Wifi or via the Topline, it takes a littel while working and it turns off again.
There are no Network found and no error indication.
After the first time, it started working again after some time. Now it happent again.
Roaming works perfekt.
Can you help me, please?

When this occurs have you tried rebooting your phone, and does it work again after that or not?

I did several times.
I’ve even removed the Akku once.
No effect.