SSL VPN Client Download / User Portal - "Can't connect securely to this page"

Hello Everyone,

I'm rather new to UTM 9, so please forgive what may be a dumb or already answered question. I am attempting to setup a Remote Access SSL VPN on our new UTM 9 instance. I've done this on many Sophos XG115 physical devices with no problems.

I've setup my profiles and users on UTM 9, but when I try to go to http://x.x.x.x:4000. I get "Can't connect securely to this page". This happens on a Windows 10 Pro client running build 16299, through IE 11. I've seen this issue before on a SonicWall, and got around it by accessing the site from a Windows Server 2012 R2, also running IE 11, and with SSL 2.0/3.0 enabled.

Given, that Edge, Chrome, and Mozilla no longer support the RC4 cipher, I know that the answer is something with the Sophos, and not simply the browser.

I would appreciate any hints or guidance.

Thank you,

Luke