Active Directory GRT restore : socket open failed

Hello

I have configured a GRT backup of a seconday AD server, NBU services are running under a domain administrator service account, NFS client services is enabled on the AD server.

The GRT backup is running fine, but when I try to browse the active directory tree in BAR interface , i get the following message : ERROR : socket open failed. (using master BAR or AD server BAR)

Any help would be appreciated

Thanks in advance

Best regards