Management access via IPSec VPN

I'm using the Home Firewall 20.0. I configured IPSec VPN to access devices in the home. I can access most devices, but not the Sophos firewall itself.

Although the VPN shows up as a zone, it does not show up as an interface (a "tunnel" interface, with an IP address that can be utilized or even configured). Therefore, I am trying to connect to the firewall using its LAN interface IP address. I can successfully ping this interface, and I have full access to other devices on this LAN subnet.

But when i try to access this IP address via HTTPS, it refuses the connection. 

Under Administration > Device Access, in the VPN row, I check all of the checkboxes (temporarily during testing). Still the firewall denies me HTTPS access.