Access is denied

I got the below error when trying to backup Server 2012 R2 Active Directory DC
Media Label: IMG001413
GRT backup set folder: G:\BEData\IMG001413
The consistency check of the snapshot for the Microsoft Active Directory, Active Directory Application Mode (ADAM) or Active Directory Lightweight Directory Services (AD LDS) database and transaction logs ntds was successful.
V-79-57344-33928 - Access Denied. Cannot backup directory  and its subdirectories.

Backup- \\VMDC2\System?State
V-79-57344-33928 - Access Denied. Cannot backup directory and its subdirectories.

 

Please help.