I have already wrote to you. Last week was impossible to solve my problem, so I wrote to my Trekstor ( e reader) support. They wrote this:
Dear Mr. žagar,
please contact the support of adobe. You have more than 6 devices activated.
Adobe must reset your account.
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Mit freundlichen Grüßen
Best regards...
Holger Hauenstein
TrekStor Service Team
So I am with you again.