This will be a user experience improvement for existing users that do not remember their credentials or enter them wrong at checkout
1. Select a plan at a "Display Plans/Groups"-view in frontend. You will now go to a checkout page. (user should be logged out)
2. Hit the "Log in" button and enter your credentials (enter the password wrong)
3. We have custom fields at our setup, so enter them as well.
4. Hit "Login and go to checkout"
5. The page will refresh and there is a message "Your password or username is wrong".
I think it would be better to ensure that the login will be checked before entering custom fields - or the custom fields value will be added to the fields.
Where you enter the login credentials there is no link to "Forgot password". This will also improve UX.
Do you understand?