NSPanel Pro disconnects from wifi

I have two NS panel pro and both disconnects from wifi constantly
One with the last update 3.0.0 the other one with v1.5.6
I have to reboot the device to connect again to the wifi network otherwise it cannot connects.
My router is a zyxel

Under the Zyxel brand are a whole multitude of routers. Which model do you have? Is it possible to be more precise? Are the two panels at a similar distance and location?

You are right, it’s a Zyxel AX600

One Panel is close to the router and the other one one floor below the router.