DFS not replicating and unable to query status

Hi,

I'm having an issue with DFS it was setup and working fine but replication has now stopped working and I'm not sure why we have 3 domain controllers all running 2012 Standard and these are also the file servers. I have included a link below to a network diagram in PDF format.

I have tried to remove and recreate the replication groups and this hasn't helped.

there are 4 folders in DFSN with an RG for each (we let DFS setup the RG with the folders originally)

http://1drv.ms/1c4Ai1a

when trying to query i get this error

PS C:\Users\administrator.domain> dfsrdiag backlog /RGName:domain.com\data\company /RFName:Company /SMem:server01
 /RMem:server03
[ERROR] Failed to execute GetVersionVector method. Err: -2147217406 (0x80041002)


Operation Failed

any ideas or help much appreciated.