Unable to create check point on Hyper V

Dear ALL,

We have recently installed Backup Exec 21.1 but I Unable to take the backup of VMs, we are getting the below error.
 

V-79-40960-38691 - Backup Exec cannot create a recovery checkpoint for the 'ZAK-MAHEN' virtual machine. Refer to the Windows Event Log on the Hyper-V host for more details or retry the backup job.

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Then I tried to create manual checkpoint but it was failed .
Hyper V 2016 Events,
'ADS2' background disk merge failed to complete: The process cannot access the file because it is being used by another process. (0x80070020). (Virtual machine ID 40970A36-59B9-473A-9628-39488234B8FA)

Checkpoint operation for 'ADS2' failed. (Virtual machine ID 40970A36-59B9-473A-9628-39488234B8FA)

Checkpoint operation for 'ADS2' was cancelled. (Virtual machine ID 40970A36-59B9-473A-9628-39488234B8FA)

'ADS2' could not initiate a checkpoint operation: The process cannot access the file because it is being used by another process. (0x80070020). (Virtual machine ID 40970A36-59B9-473A-9628-39488234B8FA)

'ADS2' could not create auto virtual hard disk C:\ClusterStorage\Volume1\ADS2\Virtual Hard Disks\ADS2_B4F1F9BC-03FE-45D3-8DDD-0C8E410AFDA9.avhdx: The process cannot access the file because it is being used by another process. (0x80070020). (Virtual machine ID 40970A36-59B9-473A-9628-39488234B8FA)
Driver Send to Microsoft OneNote 15 Driver required for printer Send To OneNote 2013 is unknown. Contact the administrator to install the driver before you log in again.

Environment Details:

Failover Cluster with 2 nodes( Server 2016)
Backup exec 21.1 with server 2019

Please suggest me how can I solve the Hyper V issue