Impossible to configure device since new wifi

Hello, i recently buy new bd4 asus wifi mesh router for my house. but some devices like my shellyplus (wich control my swimmingpool), and my envoy-s are now connected to this network, with ip address like 192.168.50.xxx, instead of 192.168.1.xxx. And now impossible to access to this device. i remove them and try to reinstall them, but impossible, i have failed to connect error. My home assistant is installed on a proxmox instance of a pc. thanks for your help.