Have you done the usual stuff? Running off of ethernet port not wifi? Tried a different ethernet port? Tried a different cable? Start from scratch on the Raspbian/Pi-hole install?
Okay so my computer and tablet work fine after I set up pihole and have my router using it for DNS server, but my phone says the network has no internet connection. Any thoughts?
Edit: nevermind, working now after restarting phone
Very large currently worked on block list.