When deploying software deployment via group policy permissons must be set so that the computer account has read permission to the install files.
To check this, open Computer Management and open Shared Folders.
Right click the deployment share and select Properties
Domain computers at a minimum should have read. In this example, I have Everyone as read.
Open Windows Explorer and navigate to the deployment folder. Right click the deployment folder
and select Properties
On the Security tab, you can see i have added Domain Computers as Read & execute, list
folder contents, and Read.
This will allow the computer accounts to access the softwaredeployment share.