Error:

Job details: Processing 155DCVM01 Error: Access is denied.
Could not perform threshold check for backup location "\\NAS-Synology\Backup\vms\09042019" due to space info retrievement fail!

Solution:

Open Registry:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam Backup and Replication

Create a DWORD: NetUseShareAccess, Value: 1