The VHD containing the replica or one of it's snapshots could not be mounted or unmounted. (ID 40002)

Issue: 

The VHD containing the replica or one of its snapshots could not be mounted or unmounted. (ID 40002)

Environment:

the backup was configured in DPM 2016 of a VM in Windows 2016, Failover cluster, which was failing with above error. the only change due to which this issue started was the Hyper-V physical server was rebooted.

Solution:

Remove and Re-Add the VM in protection group, the issue was resolved.