There are times when Notability and Google Drive stop working together. Symptoms include upload to Google Drive not working (progress bar just hangs at 40-70%), Google Drive Folders not being seen, and Notability giving various error codes on uploads to Drive.

One of the two solutions below normally fixes the problem. 

First thing to try:

1. Within Notability, open Notability preferences by clicking on the Gear icon in the bottom left.
2. Choose Manage Accounts
3. Sign out of Google Drive
4. Quit Notability (swipe it closed)
5. Open Notability and sign back in to Google Drive

When exporting a Note, Notability normally has the last used folder in Google Drive selected. Don't use that. Manually choose the folder. 

In rare cases that does not work. Try this:

1. Use the steps above to sign out of Google Drive from within Notability
2. Delete the Google Drive app form the iPad. 
3. Hard restart the iPad (hold the Home Button and Power Button for 15-20 seconds until the screen goes dark and the Apple logo appears)
4. Re-install the Google Drive app
(Re-install the Google Drive app using the Meraki app - https://youtu.be/8bzh2Iq8JUM)
5. Sign-in to the Google Drive app
6. Sign-in to Google Drive from within Notability