Windows 2016 Backup fails - Event ID 517 error code '0x807800C5'

Hi guys,

I recently installed 2 Windows 2016 servers on a Hyper-V 2012 cluster. I'm backing up to a brand new QNAP NAS with *plenty* of storage space (just checked, 11TB available). Verified the access credentials, all good. The 2012 server guests are backing up fine, but the 2016 servers initially failed with the event id 513 CAPI2 error:

Cryptographic Services failed while processing the OnIdentity() call in the System Writer Object.
Details:
AddLegacyDriverFiles: Unable to back up image of binary Microsoft Link-Layer Discovery Protocol.
System Error:
Access is denied.

I followed the steps mentioned in https://answers.microsoft.com/en-us/windows/forum/windows8_1-hardware/cryptographic-services-failed-while-processing-the/c4274af3-79fb-4412-8ca5-cee721bda112?auth=1 , but to no avail (rebooted the server too).

The backups keep failing with event id 517:

The backup operation that started at '‎2017‎-‎09‎-‎19T01:51:23.118823700Z' has failed with following error code '0x807800C5' (There was a failure in preparing the backup image of one of the volumes in the backup set.). Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.

I tried changing the backup selection as well, no success...

I have read about hotfixes for earlier releases of Windows Server. Would there be one for 2016 as well?

Any help will be greatly appreciated!

Thanks!

=== Quick update: I just configured and ran the backup on our 2016 domain controller, which is on physical hardware. Same result.



Followed by event ID 513 CAPI2, event id 517 error code 0x807800C5 and event id 1001 

Fault bucket -1483380150, type 5
Event Name: Windows Server Backup Error
Response: Not available
Cab Id: 0

Problem signature:
P1: 4
P2: 1
P3: 0x807800c5
P4: 0x80780081
P5: 0x80780081
P6: 0x807800c5
P7: 0x80780081
P8: 0x00000000
P9: 
P10: 

---

Thanks!