Combining files stopped working after previously working

[defaultz3rq4lwq1yvy]

So I've been combing files all day with the Adobe PDF pack. I have a yearly subscription with the Adobe PDF pack. I have used the combination feature four times today and now on the fifth use I get an error message "error combining cc.pdf". Why doesn't this work and why is the solution that's offered by customer service to me to buy the pro version after I've already purchased the Adober PDF pack. Can anyone help me? 

[Amal.]

Hi there

Hope you are doing well and sorry for the trouble and the experience you had with customer service. As mentioned you are unable to combine the fifth file and getting the above error message.

Is this a behavior with a particular PDF file or with all the PDFs that you try to combine after the fourth file? Please try with a different PDF file and see if that works for you. You can combine PDF files as long as they're not secure, password protected, 3D, or part of a PDF Portfolio.

Also, please try to combine the files online via Document Cloud https://documentcloud.adobe.com/link/home/ and see if that works for you

For more information, please check the help page https://helpx.adobe.com/document-cloud/faq/adobe-pdfpack-faq.html

Regards

Amal