If user management is activated in the MetaDirectory, the UCServer must authenticate itself to the MetaDirectory. For this to happen, the "Use user ID" checkbox must be set in the UCServer and a user and its password must be specified.
The query at the MetaDirectory is performed by the UCServer "by proxy" with this user. The user must therefore be activated and also configured in the MetaDirectory. The ProCall Mobile/ProCall Mac users will be able to query the contact data that the specified user is allowed to see.