If you receive this error message when trying to open your ebook it means there is a mismatch in authorisation between the ebook file and the Adobe Digital Editions (ADE) software you are trying to open it with. This can be caused by many factors. Either you have not authorised ADE yet, or you downloaded the ebook when it was authorised it with one Adobe ID, but have since authorised ADE with a new Adobe ID. Or you downloaded the ebook and then de-authorised ADE. Or the authorisation on the ebook file or the authorisation in ADE has since become corrupted, so through no fault of your own the authorisation no longer matches.

The solution to this is to reauthorise ADE and then potentially redownload the ebook.

Firstly, if you do not have an Adobe ID you need to create one here: https://account.adobe.com/

But usually if you are receiving this error you should already have one.

Please follow the steps on this help page to deauthorise Adobe Digital Editions.

Please follow the steps on this help page to authorise Adobe Digital Editions again.

Once you have done this, please try opening the ebook again. If it will not open then the authorisation on the ebook file does not match the authorisation in ADE. Please delete the file and sign in to eBooks.com and download the ebook again using a new acsm downloaded from your account.

Then once you have redownloaded the ebook please try opening it again. If you still receive the same error, you may need your download licenses reset. Please contact our support team. Make sure to quote the error message "The vendor account you entered is not associated with the item you are trying to open.", explain that you have tried all the steps in this help article and you need all of your download licenses reset.

Once our support staff has done this they will confirm. At this point please delete any previously downloaded versions of the ebook from your ADE bookshelf, and delete any previously downloaded acsm files and retry the download once more using a new acsm file downloaded from your eBooks.com account. This should resolve the issue.