Since I installed the modem Zyxel VMG8825-T50 I've been having some issues with the Wi-Fi connection. The smartphones I have work fine, but every now and then my laptop keeps disconnecting from the Wi-Fi. I also tried with another laptop and I experienced the same problem.
The laptop I have is a Dell Latitude E6430 and all the drivers have been updated. Resetting the modem Zyxel VMG8825-T50 had no effect.

Can anyone help with this problem please?

Thank you in advance!