The correct logs are the NetBackup bpfis logs on the client and the operating system logs on the client. The job details show a Windows snapshot failure: GLOBALROOT\Device\HarddiskVolumeShadowCopy..., status: 156: snapshot error encountered, and status: 1542: An existing snapshot is no longer valid. In Cohesity NetBackup snapshot processing, bpbrm starts bpfis on the client, and bpfis creates the snapshot of the client data and returns snapshot completion status. Therefore, the bpfis client log is the primary NetBackup log for the snapshot creation, mount, and delete phases.
Because this is a Microsoft Windows client snapshot issue, the Windows operating system logs are equally important. Cohesity's status 156 troubleshooting topic identifies VSS framework failures and notes that VSS- related application events may be written on the affected Windows system; it also references bpfis log content for snapshot failures. The media server bpbrm log can show orchestration status, but it usually reports what the client-side snapshot component returned. The bptm log is for media/data movement and is not the best source for VSS snapshot root cause.