setting up Windows server 2016 essentials

We are using Windows Server 2016 essentials and Comcast business class. There appears to be a firewall between the Modem and eero router we installed. 

When I set up the eero router, I set up port forwarding for Ports 80, and 443 as directed. However, when I try to connect to the web site, I see a Comcast page with a login required. This indicates to me that their is some Comcast configuration required to pass the ports through the modem.

My understanding is that I need to connect directly to the modem, and use 10.1.10.1 to connect to the Comcast set-up. Is that correct?

Do I need to set up port forwarding in the Comcast UI too and if so, what ip address do I use? The eero router provided one of the server or do I forward to the router, which then forwards to the server?

Also, these ports are not supposed to be explicitly blocked so why am I getting the Comcast Login screen?

Does anyone have specific experience with this Windows Server 2016 Essentials and Comcast Business Class?