I know this but I need an IP address.Through it's IP using a web browser.
I thought like you.I strongly suspect the ISP has locked this device to prevent access Almost all actual configurations are done with special software from the main office very similar to how cable modems are configured.
In any case here is the manual. From a quick look it does not appear you can actually change anything useful
https://fccid.io/ANATEL/03080-16-08076/Manual-do-Produto/F30E7DF7-7334-4F5D-9FAF-FC6FB21184B1/PDF