[Samba] Replication problems in Samba 4.1.18

[Peter Trifonov]

Dear all,

I have joined samba 4.1.18 (FreeBSD 9.1) to an Active Directory domain as an active directory domain controller. The domain has two other Windows Server 2008 R2 DCs.
Both windows and samba complain about replication problems.
Windows reports that replication from Windows DCs to Samba completes successfully, but replication from Samba to Windows fails with error "The replication operation failed because of a schema mismatch between the servers involved."

Samba log file has the following messages:

IRPC callback failed for DsReplicaGetInfo - NT_STATUS_IO_TIMEOUT

Furthermore, I have

# samba-tool drs showrepl
Default-First-Site-Name\GW
DSA Options: 0x00000001
DSA object GUID: 0438096c-1ec2-473e-b33d-b26bc694264b
DSA invocationId: 06f7b785-f193-47b6-b753-83f337a85710

==== INBOUND NEIGHBORS ====

ERROR(runtime): DsReplicaGetInfo of type 0 failed - (-1073610723, 'NT_STATUS_RPC_PROTOCOL_ERROR')

	
What is the reason for this problem and how can it be fixed?

With best regards,
P. Trifonov