28/02/2020 1:21:18 PM :: Failed to create snapshot (Microsoft CSV Shadow Copy Provider) (mode: Crash consistent) Details: Unknown status of async operation
The shadow copy provider timed out while flushing data to the volume being shadow copied. This is probably due to excessive activity on the volume. Try again later when the volume is not being used so heavily.
–tr:Failed to create VSS snapshot.
–tr:Failed to perform pre-backup tasks.

28/02/2020 1:22:48 PM :: Retrying snapshot creation attempt (Unknown status of async operation
The shadow copy provider timed out while flushing data to the volume being shadow copied. This is probably due to excessive activity on the volume. Try again later when the volume is not being used so heavily.
–tr:Failed to create VSS snapshot.
–tr:Failed to perform pre-backup tasks.) 

1. Make sure the VHD disk sites on the same Cluster Share Volume as the config Files
2. Make sure the Checkpoint File Location is also set to the same Cluster Share Volume