Networker 7.6.5 with exchange 2010 DAG server, failing

Hi,

3 exchange 2010 servers in a DAG group.

2 servers backing up fully, 3rd server has been failing for the last week (before hand was fine)

I am getting the following when running the job. Any idea's?

--- Unsuccessful Save Sets ---

of the file system savesets: NMM .. Operation unit failed with error Error encountered in remote agent for unit id :257, ErrorHandler invoked.

64038:nsrsnap_vss_save:NMM .. Error creating NetWorker backup of snapshot: NMM .. Operation unit failed with error Error encountered in remote agent for unit id :257, ErrorHandler invoked.

48568:nsrsnap_vss_save:PS: (CPSImportService::DeportCopy) ERR: Error calling deportCopy, status=7024:'Connection failure'

64039:nsrsnap_vss_save:NMM .. Error during deport and delete of snapshot: PS .. Error starting snapshot deport: 'Connection failure'

.

NMM .. Delete the temporary snapshot as part of deport

48574:nsrsnap_vss_save:PS: (CPSImportService::GetOperationStatus) ERR: Error for operation 2 63372:nsrsnap_vss_save:NMM .. Registration of snapshot set failed -- NMM .. Operation unit failed with error Error encountered in remote agent for unit id :257, ErrorHandler invoked 77175:nsrsnap_vss_save:NMM ..  completed commit replica with status of false.

Microsoft DiskPart version 6.1.7601

Copyright (C) 1999-2008 Microsoft Corporation.

On computer: WBCMSXMB2

Automatic mounting of new volumes disabled.

37959:nsrsnap_vss_save:An internal error occurred.

.

63335:nsrsnap_vss_save:NMM backup failed to complete successfully.

80319:nsrsnap_vss_save: Aborting session channel connection (1) to 10.18.1.95; why = Unknown error

101702:nsrsnap_vss_save: Unable to send indication to jobd: Unknown error Internal error.

102333 1436885084 3 0 0 7580 9056 0 wbcmsxmb2.westberks.local.gov.uk nsrsnap_vss_save NSR error 21 Exiting with failure. 0 ion failure'

.

NMM .. Delete the temporary snapshot as part of deport

48574:nsrsnap_vss_save:PS: (CPSImpor