TP-LINK TL-WR740N not working after installing Gargoyle

Hi guys, I recently installed Gargoyle on my router because I wanted the extra features, especially QoS. But after installing it, my Internet simply does not work on any device (typing this on my phone with my 4G) I'm not sure what's wrong. After troubleshooting the Internet on Windows 10 it says that the DNS server is unavailable

Most likely you messed up the DNS repeater in your router, OR the DHCP; Your devices get their IP, Gateway and DNS from the DHCP - so if it gives a wrong one... not working; if the router says its the DNS itselve, it has to forward the DNS queries;

Try to manually set the DNS to (YES its google) if that DNS not working, its something else, as is always avaliable ;)

Hi, I tried changing to the Google DNS server and it did not work. I'm guessing it's something else, but I can't figure it out.