Matomo breaks after nginx update

My VM is running Ubuntu 20.0.4. I follow the steps here to update nginx to the latest version:

The update completes successfully but then it breaks matomo
If I browse to https I get “This site can’t be reached / ERR_CONNECTION_REFUSED”
If I browse to non-secure (http) I see the “Welcome to nginx! If you see this page, the nginx web server is successfully installed and working…” message

I have a backup of the VM so I am able to grab previous config files (if that’s all I need to do) but I don’t know where to put them. Can anyone help?