Deleting authorisation is not possible

I try to de-authorise my MAC BOOK and this is not possible: I use the right ADOBE-account password (I set a new one to check), but I can't deactivate my computer.

The reason why I'd like to deactivate it is a fix proposed by ADOBE when books can't be loaded: the instruction states that I should deactivate & authorize my computer again. Then the book should be ok to be loaded. But without being able to deactivate my MAC this is completely useless hint.

Any tipp how to get rid of the authorisation of my MAC BOOK?