;; reply from unexpected source 127001#53 expected 1270053#53 after ubuntu reboot can not fix the nameserver

It seems like there might be an issue with your DNS configuration after the Ubuntu reboot. The error message indicates that the DNS resolver is receiving a reply from an unexpected source (127.0.0.1#53) instead of the expected source (127.0.0.53#53).

To fix the issue, you can try the following steps:

1. Check the contents of your /etc/resolv.conf file to ensure that the correct nameservers are listed. You can use the following command to view the contents of the file:

   cat /etc/resolv.conf
   

   The contents of the file should look something like this:

   nameserver 127.0.0.53
   

   If the file contains a different nameserver, you can edit the file using a text editor like nano or vim to replace the incorrect nameserver with the correct one.

2. Restart the systemd-resolved service using the following command:

   sudo systemctl restart systemd-resolved
   

   This should reload the DNS configuration and ensure that the correct nameserver is being used.

If the above steps do not resolve the issue, you may need to investigate further to determine the root cause of the problem. This could include checking for any DNS-related errors in the system logs or investigating any changes that may have been made to the system configuration