Scanning over VPN

Hello all, I am having issues with being able to scan computers while they are connected to our network through a VPN. The firewall should be configured correctly and i have turned on the network discovery and file and printer sharing in the Network and Sharing center, but still nothing. I have also created a group policy with a custom inbound rule for ICMP echo requests. The computer says that it is online in Inventory, but will not scan. Any advice would be greatly appreciated! Thanks