DIA-52604
Unable to complete the operation with the specified external end-user "string"
Cause
The specified external end-user is either the same as an existing local end-user, or the local end-user is still cached in the database shared pool.
Action
To use this external end-user, drop the local end-user with the same name and try again. If the same error occurs again, you must flush the database shared pool using the ALTER SYSTEM FLUSH SHARED_POOL statement. Another option is to specify another external end-user and retry the operation.