You cannot authenticate to a remote DPA instance from the DPA Central Server. This can happen in the following cases:
This is a side effect of one of our anti-lockout features for AD/LDAP. Many AD/LDAP servers are configured to lock out user accounts for failed passwords. To avoid locking accounts, we don't try to log on to any remote instances using AD/LDAP if you don't log on to the Central DPA with a valid AD/LDAP credential first.