This error occurs if:

  • Adobe Digital Editions has no connection to the Adobe servers.
    Check if your WifFi is working correctly and check your firewall settings.

  • the eBook is no longer in your Adobe Digital Editions folder.
    In this case, delete the document from your Adobe Digital Editions library. Then, download the title once again from your Onleihe and re-open it with Adobe Digital Editions.

  • an old version of Adobe Digital Editions is used.

  • an outdated operating system is used on your eReader (e.g., Tolino).