Pihole not working correctly on mobile devices after ISP change

[deHakkelaar]

@gasto

However, Windows is now reporting only the Pihole's IP as DNS, the way it should be:

Is that after switching DHCP to that of Pi-hole?
Because thats how it should look like with only one DNS server IP, the Pi-hole IP:

Why should Pi-hole be my only DNS server?

Reduced Ad Blocking Capability The main reason you should Pi-hole as your only DNS server is that you will see increased performance in the blocking of ads. If you have two DNS servers (Pi-hole and something else), your network clients may not always query Pi-hole for name resolution. If a query happens to be answered from a non-Pi-hole DNS server, your block lists will not apply (since that DNS server doesn't know about them). All Queries Need To Go Through Pi-hole First Since other DNS serv…

Mind though that cache is everywhere!
Reboot the devices if you suspect something is still being cached.