No connection

I recently started using it with a QNAP NAS.
I can use it for a while after installing it, but the next day it shows “No connection” and I can no longer use it. I have seen advice on this forum to install avahi-daemon, but I am not familiar with linux and don’t know how to do it. I would appreciate any advice you can give me.

If I reinstall it again, I can use it again, but after some time I run into the same phenomenon.