RAX8 will not connect to 192.168.100.1

Does anyone know how to get the RAX80 to connect to my cable modem at IP address 192.168.100.1?  I have an Arris SB8220 and the web admin page is at 192.168.100.1.  I can ping this IP address successfully.  When I try I get an error message that the site can't be reached, see attached screen shot. The RAX80 has the latest FW.

If I disconnect the RAX80 and reboot the cable modem and connect via wired ethernet I can access the admin portal.  So it seems to me that the RAX80 is not allowing access.  My ISP is Comcast and when I was using the Xfinity cable modem I could get to the CM via 10.0.0.1 address.  FYI my RAX is at 191.168.0.1 and my IP range starts at 0.2 and ends at 0.254.

Why would my RAX not connect to the SB8200 address but allow connection to other address outside the range (e.g. 10.0.0.1)?

Has anyone else solved this or is it a bug?  the Arris team states it is not their issue.  It is very disruptive to disconnect the router and reboot the CM when I want to see the CN logs.

Any support is appreciated

thank you