ScreenConnect Client Error: "An Existing Connection Was Forcibly Closed closed by the remote host"

Revup67

After being able to connect to the screen connect portal for several years, then swapping out a Sonicwall TZ 300 (with no security services) for a TZ 270 Wireless "with" Security Services such as GAV (Gateway AntiVirus) I began getting this error message:

 "An Existing Connection Was Forcibly Closed closed by the remote host"

I'd connect to a client workstation and the screen would not join the session after repeated automated tries. Reinstall the client workstation, local workstation..nothing worked but I had a hunch it was a new service that was added. Solution to follow

Revup67

The solution was to allow non SSL traffic via my subnet.

How to solve: Login into the Sonicwall device.

Navigate to: Policy | AppControl | then choose Signatures at the top.

Category #5 should be: "PROXY-ACCESS Non-SSL traffic over SSL port" if not you may need to create this.

I've attached two images of what this solution looks like. In short, I had to allow my subnet to allow non-SSL traffic outbound. By doing so, this gave immediate access to the remote workstations. An all day affair wrapped up in a simple post. Hope this helps you.

Revup67

PS: the TP Link entry is the Subnet I refer too. In essence this is the EXCLUSION that solved the issue. You may need to define your own Subnet in the Excluded IP Address Range