Can't connect to mysql server fffffor Wordpress. -Just stopped.

[David Rix]

On Ubuntu 20.04 have a WP site that was running well on home apache2 server.
A week ago got a message it could not connect to db so got a 404 Requested URL not found on server at 192.168.20.83 Port 80.

I have searched for a week and followed suggestions but still no go.

I can get into root at terminal and I can access phpmyadmin.

I see I have mysql users webmaster % and root localhost and I know both passwords.

What do I look at in phpmyadmin to change or what commands do I need to do to get it back working please?

Thank you