More helpful information about Google and Facebook
show an error message when user can't authenticate by `authenticate_user_login()` call
show an instrutive error message when user can't authenticate via `authenticate_user_login()` call
show an instrutive error message when user can't authenticate via `authenticate_user_login()` call
possible cause is email registered by another auth plugin
correct urls to login page and forgot password
correct urls to login page and forgot password (cast to string)