LDAP_REFERRAL (10) - the server is referring the client to another server
Errors Troubleshooting UnitySync
These errors may occur in the Discovery or Sync phase.
The error generally indicates that while we can see the domain or structure in question, the attempt to read or write to the structure was unsuccessful.
For example, this may occur on Discovery when trying to read a DC that allows us to see trusted domains. We can see the trusted domains, but the actual attempt to query the trusted domain on Discovery results in a Referral error; that is, Discovery is unable to follow the Referral to read a trusted domain. We can only read the actual domain or child domains of the forest if pointing to the Global Catalog. In this case, Exclusions or a Selection DN should be used to avoid querying the trusted domains.
On Synchronization, this error is a little more tricky. It may indicate an unexpected change to Destination structure (Structure Name or Placement DN) and the next Sync run may be trying to Modify or Move objects from the old structure that we no longer have access to.