Check error activation and not able to remove autorisation

Hello, 

I want to open my book in Digital Editions, but I get the notification "Check error activiation". However, my computer is autoritized and als my e-reader it says. When I try to remove my autorisation I can't. It reports: not possible to remove autorisation, try again later. I've tried it last week and again today, without succes. I've tried to cchange my password, make another account, delete the program and reinstall it, all without succes. Please help. I can't read any book now on my e-reader. 

Regards Marina