After startup of the system, what does systemctl status systemd-resolved.service say?
Do you find anything suspicious in the logs? Warning or error message from systemd-resolved? Is the service enabled?
09:42:40 systemd-resolve: Using degraded feature set UDP instead of UDP+EDNS0 for DNS server 192.168.40.1.
09:28:31 systemd: Started systemd-resolved.service - Network Name Resolution.
09:28:31 systemd-resolve: Defaulting to hostname 'fedora'.
09:28:30 systemd: Starting systemd-resolved.service - Network Name Resolution...
09:28:30 sudo: alex : TTY=pts/0 ; PWD=/home/alex ; USER=root ; COMMAND=/usr/bin/systemctl start systemd-resolved.service
09:28:26 systemd: Stopped systemd-resolved.service - Network Name Resolution.
09:28:26 sudo: alex : TTY=pts/0 ; PWD=/home/alex ; USER=root ; COMMAND=/usr/bin/systemctl stop systemd-resolved.service
09:28:16 systemd: Started systemd-resolved.service - Network Name Resolution.
09:28:16 systemd-resolve: Defaulting to hostname 'fedora'.
09:28:16 systemd: Starting systemd-resolved.service - Network Name Resolution...
09:28:16 sudo: alex : TTY=pts/0 ; PWD=/home/alex ; USER=root ; COMMAND=/usr/bin/systemctl restart systemd-resolved.service
09:27:57 systemd-resolve: wlp2s0: Bus client reset DNS server list.
09:27:34 systemd: Started systemd-resolved.service - Network Name Resolution.
09:27:34 systemd-resolve: Defaulting to hostname 'fedora'.
09:27:34 systemd: Starting systemd-resolved.service - Network Name Resolution...
09:27:34 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:34 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:34 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:34 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:34 sudo: alex : TTY=pts/0 ; PWD=/home/alex ; USER=root ; COMMAND=/usr/bin/systemctl restart systemd-resolved.service
09:27:30 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:30 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:30 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:30 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:30 systemd-resolve: Failed to send hostname reply: Transport endpoint is not connected
09:27:24 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:27:21 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:27:12 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:27:09 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:27:00 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:26:56 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:26:47 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:26:44 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:26:35 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:26:32 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:26:23 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:26:20 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:26:10 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:26:07 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:25:58 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:25:55 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:25:46 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:25:43 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:25:34 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:25:30 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:25:21 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:25:18 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:25:09 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:25:06 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:24:57 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:24:54 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:24:44 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:24:41 systemd-resolve: Using degraded feature set UDP instead of TCP for DNS server 192.168.40.1.
09:24:34 systemd-resolve: Using degraded feature set TCP instead of UDP for DNS server 192.168.40.1.
09:24:28 systemd-resolve: Using degraded feature set UDP instead of UDP+EDNS0 for DNS server 192.168.40.1.
09:24:10 systemd-resolve: wlp2s0: Bus client set DNS server list to: 192.168.40.1
09:24:10 systemd-resolve: wlp2s0: Bus client set default route setting: yes
09:24:10 systemd: Started systemd-resolved.service - Network Name Resolution.
09:24:10 systemd-resolve: Defaulting to hostname 'fedora'.
09:24:10 systemd: Starting systemd-resolved.service - Network Name Resolution...
09:24:10 sudo: alex : TTY=pts/0 ; PWD=/home/alex ; USER=root ; COMMAND=/usr/bin/systemctl restart systemd-resolved.service
As you can see - initially there is something wrong, until I manually restart the systemd-resolved.service
Private DNS often do not meet modern specifications.
This can lead to various issues such as timeouts and denial of service.
Consider replacing your private DNS with a public DNS provider.
Hi again. Eventually I followed this part from the post you suggested:
You can try to switch in nm-connection-editor the wireless to IPv4 “DHCP addresses only” and specify 192.168.156.1 as DNS server. This forces use of Fritzbox DNS relay, which probably refers to the other ones but knows the internal addresses too. Search domain is fritz.box.