[Samba] Error when adding user NT_STATUS_CONNECTION_REFUSED

[lp101]

Any idea what the following error message is describing and how to 
troubleshoot? Newly joined DC. Using Ubuntu 12.04 and Samba 4.1.4 from a 
tarball. Used samba-tool. Windows Users & Computers app gives error as well.

ERROR(ldb): Failed to add user 'usertest':  - 
../source4/dsdb/samdb/ldb_modules/ridalloc.c:547: No RID Set DN - 
Request for remote creation of RID Set for this DC failed: Failed to 
send MSG_DREPL_ALLOCATE_RID to dreplsrv at 1054: 
NT_STATUS_CONNECTION_REFUSED