There are many reasons why it's not possible to register or login. A space before or behind your email address causes the error message saying that you have to enter an invalid email address.
It is also possible that there is a space behind your password. Also keep in mind that passwords are case sensitive.
If you're still not able to register/log in, please don't hesitate to contact our customer service at firstname.lastname@example.org. We will be happy to help.