Thanks for replying.

Router is:

Zyxel
Model number: P-660HW-T1 V3

It was provided by my ISP and I need to use it in order to connect to their service. I cannot just replace it by any other router, since it is configured to connect to their service and the router is locked, I don’t have the password to access configuration.

The ISP would not lend me a router.