De-Authorisation does not work

I currently cannot opem ebooks I bought with Adobe DRM. When I try to install the .acsm files, I receive the error message: E_ACT_NOT_READ. When I try to de-authorise my Mac, I also get an error message saying I should try again later. But that does not help either. I installed the newest version of Digital Editions, still the same issues. What can I still do?