Have you found such kind of issue on your VMware backup paltform?
As a result sometimes blocking your backup job and nobody has made any changes.
All you need to do in order to fix this issue is pretty simple.
Disable the VSS service on each of your own VMs. By default when you installed VMware Tools, VSS is default option. Hence you might not aware it replace built in VSS windows service.
Don’t worry since no downtime required to perform this task, even reboot. You can go ahead to control panel and select VMware Tool for changing.
Choose custom and deselect volume shadow copy feature.
Click next and here you go!
You may to re-start the backup process and see the outcome.