Hello @Abhishek Singh
Backing up VMs using Cluster Shared Volume (CSV) or Scale-Out File Server isn't supported. CSV writers are likely to fail during backup. On restore, disks containing CSV volumes might not come-up.
Refer to support matrix - https://learn.microsoft.com/en-us/azure/backup/backup-support-matrix-iaas
------------------------------------------------------------------------------------------------------------------------------
Please do not forget to "Accept the answer" and "Up-Vote" wherever the information provided helps you to help others in the community.