The router's wifi disappears when I connect my mobile

[QVENGADOR]

I have always had the possibility of having wifi for my mobile. But recently, if I turn on the wifi on my mobile, it turns on but after a short time it turns off.
Could you give me some clues on where to look.
Thanks for reading me.

[Franziskaner]

Don't you have some kind of energy saving set up on your mobile phone?
Greetings

[cobito]

You must provide more details about the problem.

Do both the mobile and PCs connected by wifi have the DHCP client active? What model of router do you have?