We just experienced this error with a hosted feature layer on ArcGIS Online.
The item was owned by the same user used by the GE Data Stores Registered server connection, and was in a user subfolder (not root) on ArcGIS Online.
Conclusion (cause): The AGOL folder was corrupted in some way.
Our Solution: Change ownership of item in the folder to yourself, delete the folder, recreate the folder, then change ownership of all the items back to the original user and recreated folder. (Obviously, this is going to require some administrative privileges.)