Wireguard VPN not resolving pihole+unbound DNS

Hi everyone,
I have a CasaOS setup on armbian on which I installed Pihole+Unbound. It works perfectly line on my local network, blocking ads and resolving DNS for everyone on the network.

I installed Wireguard Easy so that I can remote into my network and use Pihole adblocking but while I can access the local network, I cannot access the Internet.

This is my setup:

Pihole+Unbound: big-bear-pihole-unbound 2024.07.0
I set Permit all origins and started the pihole after wireguard, but still nothing can’t access the Internet.

Wireguard easy: wg-easy 13
WG_ALLOWED_IPS 0.0.0.0/0
WG_DEFAULT_DNS 192.168.0.121 (pihole)
WG_HOST <server_public_IP>
WG_PORT 51820

On my browser, I get the error DNS_PROBE_FINISHED_BAD_CONFIG.
If I change WG_DEFAULT_DNS to something else like 1.1.1.1, I get Internet access.

What could be the issue?