My ipFire router blocks and thus its origin

my ipFire router blocks and thus its origin.
When I try to access or a subdomain like, my page remains empty or the website cannot be found. Even a ping to directly in the shell of the router does not give any feedback.
The situation is different on the Fritz.Box in front of my router because everything works fine there. However, I have not found anything suspicious in the ipFire logs.
Basically, the DNS resolution works and it seems to only affect this domain.
What else could this be?

IPFire 2.25 (x86_64) - Core Update 154


MfG Paul

I have found the cause but do not really understand why this is the case. When I enter the IP as DNS server from Google, I cannot connect to and the message “Reverse lookup failed” appears. If I enter the IP of as another server, for example, access to the website works. I have now kicked out Google and that should be the solution for now.

This is how it works