Behavior:
Error Message in ADSync.log:
Failed to synchronize ldap user CN=BRIAN FORD,CN=Users,OU=User Sync,DC=DOMAINNAME,DC=COM to DocuWare group GROUPNAME.We expect the user to be an existing DocuWare user, but he is either not active or we failed to match him while syncing users by either externalId, externalProvider or name and email</message></event>
Solution:
By customer request, non-unique-attributes for User Synchronization Version 2 were introduced in DocuWare version 7.5.
If you want to use these attributes, you need to keep in mind, that these fields must be unique in DocuWare:
Loginname
NetzworkID
InternalID