Dear @N1Marc,

N1Marc wrote

I'm using my ISPs router in bridge mode (since I have cable internet) so shouldn't it be enough to set my WAN Port to dynamic IP and that's it or am I missing something? At least thats how I use my current router. I get an IP from the DHCP so the router itself seems to work fine, but I can't get an internet connection going. In the Omada controller it says: "[Failed]Router failed to obtain the IP address for WAN because no response from the server." 

Some ISPs' router may only be able to cache one MAC address, once it caches the MAC address of a router and provides an IP address for the current router to access the Internet, it may fail to recognize another MAC address from a new router.

Try unplugging the power from your ISP router completely (take out the battery if any) to remove its memory for MAC address, wait for couple minutes and then plug the power back and hook up with ISP router with the new Router for Internet connection.

Dear @N1Marc,

N1Marc wrote

But plugging it into the WAN port and setting it to dynamic IP should work? Do i still need to give access to the internet to the lan port or is that a default setting?

If your current existing router is configured with Dynamic IP for Internet access, then it should be the same for the ER605.

Topology: ISP Router (Bridge mode) -----(WAN) ER605 (LAN) ----- PC

With the connection above, ER605 will use Dynamic IP to connect by default.

If you cannot get Internet access on your PC, try the earlier suggestion for checking.