Differential backups are failing due to IaaS VM image backup and Vss service being run

Hi All, Differential backups are failing due to the vm image backup and vss service being run,the organization policy is to take both vm backup and the diff backup daily which seems to be not possible,initially i have configured the backups using maintenance plans and later knowing the issue i have reconfigured using Ola Hallgren's solution using the parameter changebackup type='Y' without any luck. Diff runs successfully immediately after a full backup but not on the scheduled times(EOD 9PM everyday) Any suggestions on how to get the differential backup working without changing the vm backup schdule and vss service? Thank you, BT