Using degraded feature set TCP instead of UDP for DNS server

I periodically experience a disconnection with my laptop. The connection period lasts about 3-6 minutes. I know for certain that the WiFi works fine.

Using the command sudo journalctl --since="-2 minutes" I find that a recurring line is:

(...) Using degraded feature set UDP instead of TCP for DNS server 10.64.10.16.

What should I do ? I cannot work since the connection conditions are definitely unstable. I have recently noticed that it is a quite common problem.

I have ubuntu whose version is 21.04, and my laptop is an Acer Aspire 3 A315-56 with a WiFi connection.

I had advised doing the following:

1. Set DNSSEC=no in /etc/systemd/resolved.conf
2. Use another DNS server than that of the ISP (such as Google Public DNS)
3. Disable IPv6 in the local network (is perhaps not helpful).

The poster has reported doing this:

I have set DNSSEC=no (commenting it out) through the command:

sudo nano /etc/systemd/resolved.conf

After that the cmd:

sudo systemctl restart systemd-resolved.service

with a reboot.

For changing the DNS servers, the poster has followed the article
How to Set DNS Nameservers on Ubuntu 18.04.

For the moment, the poster's system seems stable.