Hi victoriap19600982, Please try combining PDF files after signing in at "https://cloud.acrobat.com/combinepdf" using your Adobe ID credentials. Also, make sure that the files you are trying to combine are not secured, password protected, 3D or part of a PDF portfolio as these cannot be combined. If you're combining supported file types and still getting that error, please try the following: Log out and clear the cache. Then log back in to https://cloud.acrobat.com/combinepdf using a supported web browser (see: Technical specifications | Adobe Document Cloud). Try combining smaller groups of files, to see if you can narrow the error down to a specific file or files. Let me know if that helps. Regards, Anubha
... View more