I am having the same issue on a VersaLink C505S
I have been informed by developement that the issue has been fixed and the app should be working again.
Having the exact same issue on the same machine at the same customer as when posted on 11-18-2020. Scan to Cloud Email was working until about 4:30pm today, 1/20/2021, when the Scan to Cloud Email App shows 'Completed' but the scan is not delivered to the customer's inbox, junk/spam, etc. Please let me know when this is addressed on the Xerox end so I can advise customer. Thank you.