CloudKit Error "User Deleted Zone" (28/2042)

In my app, one of my users is no longer able to access the application iCloud container. The log file contains these errors:

<CKError <redacted>: "User Deleted Zone" (28/2042); 
server message = "Zone was purged by user"; 
uuid = <redacted>; container ID = "iCloud.<redacted>">

• Has anyone an idea on what the user may have done to unlink the app from his iCloud storage?
• How should I react within my application to this error to get it "back on track"?