Xperia P can't see wifi on Zyxel Router

[divnejpatron]

I'm afraid, that the Sony Xperia P has a problem connecting to routers Zyxel. Especially with the NBG-416N router, but I had problems with some others. I've tried everything. Disconnect, reset the router, set different WiFi modes, but without success. I can see all the networks around, just not my network. Can someone help, please?
Does anyone know what could be the problem? I am already hopeless.

Thank you for your answer, MN.

[muncla]

I solved this problem, in ZYXEL router must be manually choosen channel of WiFi, when it is on auto state, it is not functional, when it is such as on channel 1 - 2412MHz it is good, on higher frequences it may not be functional.