DAG Exchange 2013 backup failled

Hello,

I'm trying to backup an exchange 2013 DAG, based on w2012 R2 , Networker version is 8.2, NMM version is v3

There is 3 DB on the DAG , DB001 / DB002 and DB003

On NMC, inside my client,  config is :

NSR_SNAP_TYPE=VSS

NSR_VSS_FORCE_SYSTEM_PROVIDER=yes

CIRCULAR_PROMOTION_POLICY=Promote

NSR_FEDERATED_BACKUP=yes

NSR_EXCH_INCL_SA=FALSE

NSR_ALT_PATH=D:\Snapshot

NSR_EXCH_DAG=EXDVDRDATOT007.eq1tot.lan  ( DAG 's name )

NSR_EXCH_BACKUP=active

NSR_EXCH_CHECK=no

Backup failled with this message :

APPLICATIONS:\Microsoft Exchange 2013: Backup of [APPLICATIONS:\Microsoft Exchange 2013] failed

EXCH_CHECK=no -A NSR_PARENT_JOBID=65959 -A snap_sessionid=

Starting slave backup job on host : EXDVDRARTOT003.

51340:nsrsnap_vss_save:jobhandler(340): Created Job ID: 65970

  Save command: nsrsnap_vss_save.exe -s labces1nsr2 -g exchange2013 -m EXDVDRDATOT007.eq1tot.lan -l full -W 78 -LL -Z EXDVDRDATOT007.eq1tot.lan -A optype=conventional -A NSR_SAVE_FROM_SAVEGRP_NSRSNAP=Yes -A NSR_SNAP_TYPE=VSS -A NSR_VSS_FORCE_SYSTEM_PROVIDER=yes -A CIRCULAR_PROMOTION_POLICY=Promote -A NSR_FEDERATED_BACKUP=yes -A NSR_EXCH_INCL_SA=FALSE -A "NSR_ALT_PATH=D:\\Snapshot_Networker" -A NSR_EXCH_DAG=EXDVDRDATOT007.eq1tot.lan -A NSR_EXCH_BACKUP=active -A NSR_EXCH_CHECK=no -A NSR_PARENT_JOBID=65959 -A snap_sessionid=

85940:nsrsnap_vss_save:Slave backup with job id (65969) failed on host 'EXDVDRARTOT004'

85940:nsrsnap_vss_save:Slave backup with job id (65970) failed on host 'EXDVDRARTOT003'

115725:nsrsnap_vss_save:One of the slave job failed, sending Failed Sync Signal

nsrsnap_vss_save: Exchange federated ..Updated saveset response with hresult 0x54f.

Internal error.

102333 1481640470 3 0 0 17808 17636 0 exdvdrartot005.eq1tot.lan nsrsnap_vss_save NSR error 21 Exiting with failure. 0

In NMM.raw , I have this errors :

NSR info NMM .. checkFor447Errors = 1, checkFor448Errors = 1, DAG Name [EXDVDRDATOT007].

NSR info NMM .. start the creation of a replica. Replica will be of type Default - which is VSS determined  Non Transportable.

NSR critical NMM.. Exception caught: Failed to create replica.

NSR critical RM ..  INFO:Progress in PrepareDiscover phase is 0 percent.

NSR critical RM .. 026671 ERROR:A COM error occurred while validating the version of Exchange. The error code is 0x80010105. The error message is: The server threw an exception..

what i've already check :

nsrsnap_vss_save -v -? done on all nodes => everything seems to be fine

nmm checker was all good when i did it

Reboot all nodes of exchange DAG done

Start /stop  VSS service etc etc done

If someone have an idea i'll take it :-) , i'm new in Exchange backup so please don't hesitate to tell me if something missing .

Thanks in advance,