ConnectPort Portal not accessible from another subnet

I have 3 ConnectPort TS 16 Devices on a Subnet (, for example)

I am trying to access the Portal pages for the devices from Servers on a different Subnet ( It works for about 4 minutes before I get an error in a web browser saying that the IP of the connectport device took too long to respond

Outside of the ConnectPort Devices, Communication between the two Subnets is perfectly Fine. I can connect top other unrelated devices to and from each side. I am even able to Ping The Connectport Devices directly from the Other Subnet when this issue is happening.

If I log into the ConnectPort devices (from pc on same subnet) and use the Ping utility, I am unable to Ping the Gateway IP of the other subnet.

I worked with the Firewall vendor, and they pointed out that the ConnectPort Devices were sending ACK_RST packets, causing the connection to partially drop in this odd way. Does anyone have any idea why this would be? Are there any suggestions out there?