Staff members using OneDrive, if your OneDrive has little or no memory space this can affect the download process. Make room on your OneDrive,by unauthorizing then re-authorizing your Adobe Digital Editions and trying the download process again.
Alternatively, you can change the download location away from your OneDrive. In Firefox go to Tool/Options/General/Always ask me where to save files. Then you can choose a different location for the downloads.
If your Adobe Digital Editions (for Desktop) is giving you an error message, a quick-fix could be to unauthorize and re-authorize it.
Do this by holding Ctrl + Shift + D and then re-authorizing it under the Help dropdown.