VM backup is failing

Hi All,

NBU VERSION: - 7.6.1
OS - 2012

One of my vm client backup is failing with 156 and Vm team able to create and delete the snaps manually and system writers are also stable on the server side.

Error from detail job summary :-

Vmware_freeze vixapi freeze (VMware snapshot) failed with 1 - unrecognised error
An error occurred while saving the snap shot :failed to quiesce the virtual machine

Vfm_freeze

Please confirm whether “virtual disk” service is required mandate to start in the server as its in stopped state .