dns error on admin page and ads are not blocked on websites

Expected Behaviour:

  1. When I open the url http://pi.hole/admin the admin page should be opened.
  2. When I call the website www.kicker.de the ads on the page should be blocked.

Actual Behaviour:

I can access the internet on all my devices, but…

  1. I get an DNS_PROBE_FINISHED_NXDOMAIN error in chrome when accessing http://pi.hole/admin.
  2. The ads on www.kicker.de are not blocked.

Debug Token:

4fge33bt75

Can you post output from below one run on one of your client PC’s (can be Windows/Linux/MacOS):

nslookup pi.hole

Did you setup shop like described in below docs or other ?

https://docs.pi-hole.net/main/post-install/

Your debug log shows Pi-Hole is working normally, but has only received queries from the Pi. There is likely a problem in the DNS settings of your router and / or clients.

@deHakkelaar yes, I use a FritzBox 7530 and I set the pi-hole as DNS for my local network devices.
(Menus “Heimnetz->Netzwerk->Netzwerkeinstellungen->IPv4 Adressen->Lokaler DNS-Server” and “Heimnetz->Netzwerk->Netzwerkeinstellungen->IPv4 Adressen->DNSv6-Server im Heimnetz”)

First I entered the Pi also as the DNS into the menu “Internet->Zugangsdaten->DNS Einstellungen”, where the WAN DNS server configuration is made. I deleted this now and put in the google dns

nslookup pi.hole says

Server: raspberrypi
Address: fd00::7222c:a7d1:65ee:b555

DNS request timed out.
timeout was 2 seconds.
Name: pi.hole
Addresses: fd00::7222c:a7d1:65ee:b555
           192.168.178.3  

The addresses are correct. I use the DHCP of the FritzBox and assigned these addresses to the pi.

I believe you’ve done too much and maybe created a DNS loop somewhere causing heavy load on Pi-hole resulting in those timeouts.
Only enter the Pi-hole IP address on the Fritzbox DHCP settings page as a single DNS server and no others!
Default the rest of the router settings.
And I believe Fritzbox needs some more tinkering with its settings (maybe rebind protection).
Search discourse here for Fritzbox or wait for another Fritzbox user that knows.
I believe there are plenty.