Are you using the interface built into the free Adobe Reader, or are you uploading directly? If it's Reader, then try to upload to the service: http://cloud.acrobat.com/exportpdf - does that work? In my experience, uploading directly is a lot more reliable than using Reader.
We are sorry for the inconvenience caused to you.
1.Please let us know the Reader version from Help > About Acrobat reader DC. Update to latest version from Help > Check for Updates
2. Are you experiencing this for a particular file ? Please share the file if issue is file specific.
Please check if you are able to successfully export from online service: https://cloud.acrobat.com/exportpdf
Kindly share a snapshot of the error message you observe?
Thanks very much , you saved precious time of my day!
It works now...and it works much better straight from cloud acrobat than acrobat reader.