I was trying to create a geometry dash account. It kept saying "invalid email". How can it be invalid when it's the only email I have?
I solved it by registering here.
I found this link by clicking the "help" button in the login dialog and guessing the file name of the registering page.
If you don't trust me, you can get to that page by clicking that button by yourself and changing the file name to "register.php".
UPDATE: I guess they have deleted that page now, and I can't find an alternative to that by searching
register site:boomlings.com. However, I found this: http://www.boomlings.com/database/accounts/invalidEmail.php