I suddenly was unable to remove DRM from all Adobe epub books. I was able to resolve the problem with the following fix: Open Windows Security. Go to Virus and Threat Protection. View Protection History. If there is an item "Protexted folder access blocked" click the down arrow to check whether the block was for EPUBOR OUTPUT. If yes, then click the link to controlled folder access settings. Then in Controlled Folder Access, select the link to "Allow and app through Contolled folder access." Click " + Add an allowed app." Choose recently blocked apps. Choose to allow Epubor.
The ebook is readable only on Adobe Digital Edition