"Could not connect to server" when incorrect password given

[Aaron1011]

If a user provides a correct username (meaning a user with that username exists), but an incorrect password, the game attempts to connect to the server, then displays "Could not connect to server". There should be a nicer message letting the user know that their login information was incorrect.

[brynnb]

Trying to connect with an account already logged in gives the same error, would be nice for useful error message.

[sergkr]

I'll try to take this one in my fork. Adding some additional details below.

Besides the generic / unhelpful error message, another (possibly worse) issue is you cannot return back to the login screen if you mistype the password without refreshing the browser. I think rather than navigating away from the login form and launching a non-functional game with broken UI, it would be better to make a separate request to the server to check the username/password. If it is incorrect, then we display a validation error right in the login form.