Please check your credentials.
If you are sure, that account and password are correct, the following reasons may be possible:
Case 1 (password has been changed – Delayed activation):
For technical reasons, there may be a short delay after a password change until the new password can be used. In this case, please use this link and try again.
Case 2 (password has not been changed – UniAccount disabled):
On 27.01.2015 the passwords, that havent been changed by the user, were disabled for security reasons. With this link you have the opportunity to catch up on this. This will reactivate your UniAccount.