I've emailed you a couple times about this issue and am still awaiting a response. I have Chromebooks which do not have editable PDF capacity so am using the free dochub with my students. However, some students filled-in PDFs do export correctly to Google Drive and classroom while some do not. On some days, dochub keeps student edits and other days it does not. Are you having server problems? I've also not received any replies despite a couple support requests I've filled out. Is there a number I can call you at to discuss?
Dochub not keeping edits/saving, also not exporting/integrating with Google Drive/Classroom