We apologize for the inconvenience caused, as per the description above, you are getting an error while converting a PDF file into Excel, Is that correct?
Please try to convert the PDF file to Excel using the URL https://cloud.acrobat.com/exportpdf with your Adobe ID and password on a different browser like Chrome, or Firefox, or Safari and see if this brings any difference.
If you are using the free desktop version of Adobe Reader DC and getting the error message, please sign out and sign back in Adobe Reader using your current Adobe ID and password and check for any pending updates of Adobe Reader from Help>Check for updates.
Have you tried converting any other PDF file into Excel? If not, please try converting any other PDF file into Excel.
Are you getting the error while converting one specific PDF file or with all the PDF file?