IPV4 Firewall Lan to Wan rule blocks internal communication with DVR
I have a surveillance DVR on my LAN. It is managed, and recordings viewed, with software from a PC. Both are on VLAN1 (192.168.1.0/24). Both have fixed ip addresses within that range. As a security measure I want to prevent the DVR from communicating with the internet. Offsite access is not required. I've set up a firewall rule which blocks traffic from the DVR IP, which is source configured as "Cobra_DVR" IP group. See below. The rule direction is LAN->WAN, and WAN IN.
The problem: This rule prevents the software on the PC from communicating with the DVR. If I remove the LAN->WAN direction, leaving only WAN IN, the problem goes away. Since both devices are on the same VLAN, why is this happening? Is there a way to correct it?