I have 2 connections: wired (Ethernet) and wireless (Wi-Fi).
I definitely set my Wifi not to connect automatically in Network Settings. So re-connection cannot be the issue. I do use Network Manager.
When I click on Disconnect button in Networks pop-up, there is a bit of visual feedback, but no disconnection. The button re-appears and still labelled with “Disconnect” and there seems to be increased traffic on that interface for a short while after the click. So something happened - but it wasn’t a successful disconnection.
There is no hint in dmesg that any disconnection took place.
Which log I should look at?
Are you trying to disconnect WiFi on your local machine or the remote machine?
And, is your VNC connection over the wired or wireless connection?
TSU