Error backup Hyper-V 2012

[Jonbs]

I have the following error message on two HyperV-V 2012 platforms have reinstalled twice agents and error, which could not be removed?

Backup- VRTSRV::\\H----------\Hyper-V?HA?VM\SRDCHM02

  Unable to attach to .

V-79-57344-33899 - The resource could not be backed up because an error occurred while connecting to...

Backup- VRTSRV::\\H---------\Hyper-V?HA?VM\SRPRINTHM01

  Unable to attach to .

V-79-57344-33899 - The resource could not be backed up because an error occurred while connecting to...

Exceptions

Backup V-79-57344-34009 - An error was encountered creating on-disk catalog. If this is an incremental back... V-79-57344-34009 - An error was encountered creating on-disk catalog. If this is an incremental back...

[pkh]

Turn off GRT and try again

[Jonbs · Accepted solution]

In the end it was a problem of the agent of one of the appliance, it was corrupt. 
Download a new version of the agent.