And one that leaves you not knowing how to the the most basic things. This is why the standard install is recommended…
The problems you’re have with their console suggest that they haven’t updated the base image, as new Ubuntu installs “just work” with the new web based console, another way that the one click hurts people. That said, if you can log in with putty then you don’t need the web console.
“sender mismatch” sounds like you need to run discourse-setup which will let you set the notification email address. Another way would be to create an admin account with
./launcher enter app
rake admin:create
And then change notification email in site settings.