Port opening on Zyxel p8702n with NextGenTel connection

[Strigops]

Hello,

We moved to Norway recently, and are renting an appartment. Included in the rent are the TV and internet connection. The landlords have a separate internet connection from NextGenTel for our appartment, but are using a Telenor router for the wifi. The internet is working fine, no problem.

However, now we want to open a port for playing online, and we can't figure out how to do it. The main problem is that we can't connect to the router for changing the settings. The router is a Zyxel  p8702n from Telenor, and when I go to the IP-adress (to access the router), I get the Telenor screen to say I'm connected to the router,  but I can't access the router settings, since "You must be connected to your home network in order to manage your router. If you are on 4G you will need to switch to wireless network in settings." I guess the problem is that the connection is not a Telenor one, and that's why the router is complaining. 

Does anybode has an idea how to fix this, or had similar experiences?

Thanks in advance!

[Hårek]

Telenor has disconnected local management of this router, they have a Web interface.
It should be possible to reinstall older software on the router to get back local control. See this thread: