After Effects K12 License Problems

I own a K12 License which I got cheaply from my school. It was indeed complicated and a pain in the ass in setting it up, but now all my creative cloud application run smoothly. Except after effects - while all other application start perfectly, after effects tells me that my trial version is expired and that I need to buy a license.

I have already tried the RemoveVolumeSerial - AdobeSerialization approach like a friend told me. What else can I do to get my after effects up & running?

Thanks in advance,

greetings from Germany

Vincent