I have a router and when I turn the DHCP off I can no longer connect to the configuration page. Is there a reason that I shouldn't be able to connect or is the router broken? If I am doing something wrong then how could I go about fixing it?
If you identify/configure the static IP address of your router, you should be able to assign a static IP address to your connecting device within the same subnet and navigate to the WebUI.
If your router is a TP-Link like your tag suggests the default IP may be 192.168.1.1 with a /24 mask.