wi fi – Nokia 7.1 / Android 9 can not connect to a specific local IP address

My configuration

  • Raspberry Pi using Pi-Hole over static IP 192.168.0.200
  • TP-Link Archer C7 router
    • IP – 192.168.0.1
    • DHCP Configuration
      • Default Gateway – 192.168.0.1
      • DHCP range 192.168.0.100192.168.0.199
      • DNS – 192.168.0.200 primary, 8.8.8.8 secondary
    • The wireless point-of-access isolation is disabled

I have a new Nokia 7.1 under Android 9. It connects well to wifi (receives an IP address like 192.168.0.103, DNS settings are set correctly) and can access the Internet as well as some local IP addresses such as the router's administration page and other devices connected to the network, for example a Synology Diskstation.

I noticed that ads were appearing on some web pages. I've therefore tried to access the pi-hole dashboard to check. When I tried to access http://192.168.0.200/admin, I receive

This site is not accessible

http://192.168.0.200/admin is inaccessible
ERR_ADDRESS_UNREACHABLE

this explains why I received ads but could not understand why the phone can not access this specific local IP address.

My laptop that is on the same wifi network can access the pi-hole dashboard without any problem.

This is my first Android 9 device, so I may miss a specific network setting. Previously, I had a Nougat phone that did not present any such problem.