I'm running a WDR4300 which works like a charm. Now I bought a used Archer C7 AC1750v2 with already installed OpenWRT 17.xxx. I did not have the password, so I bootet it into failsafe. Via SSH I executed the commands "firstboot" and changed the password. Rebooted it. It serves an address via DHCP to my client, I can log into it via SSH but the GUI on 192.168.1.1 is not accessible in a browser. Tried different browsers. But the GET request is not answered and the web interface of the router just does not show up in the browser.
Any ideas how to fix it? I know my ways around networking but have just about 0 expertise in linux.
Flash 18.06.1 via ssh and using sysupgrade -n <openwrt c7-v2 sysupgrade image>, this makes sure that you're running an image that actually includes luci and that all potentially pre-existing (mis-)configurations are reset to defaults.
I just installed a tiny http-server on my pc and downloaded it via wget to the router. Then used sys upgrade -n and now I'm able to access the router again! Thanks a bunch for the quick help!