Getting message "too many activations made"

Why can not I read my ebooks? You are always asking for the DRM and giving the message "too many activations made". How can I overcome this problem? This leads me to not subscribe to any Adobe service, and if after I pay, the program starts giving errors for which Adobe has no solutions.
Thank you

[Moved from the Lounge (which is where you can "connect with your peers" from across all of Adobe's products for conversations that don't directly relate to help and support) to a product-specific support forum. Also, edited title for brevity. - moderator]