SAMBA 4 - Can not create user

SAMBA 4 - Can not create user

When trying to create a user in SAMBA 4 I am always returned with :

Error Code 800706ba : User account cannot be created - Error in setting password, The RPC server is unavailable. 

Known limitation in ADManager Plus?

Tried restarting all SAMBA pieces and updated to latest ADManager Plus.

Thanks,
JES