The first step is to check whether you have definitely entered the activation code correctly. Pay attention to upper and lower case letters .
The next step is to check that you have selected the right school. You can see this on the login page at the top.
In this example the school is called "Sdui GmbH".
If the school name is not correct, click on "change" to start the school search again.
If the activation code has been entered correctly, the school name has been selected correctly and the problem persists, please contact your Sdui contact person at the school. They will need your full name and activation code for troubleshooting.