Help with Flint connection

Does anyone know why I am not able to connect my server Flint router to my home ISP router without getting a can’t connect to internet message?

I connected my Flint router to home ISP router via Ethernet to Wan. The network will connect but then drop saying something like connected but unable to access internet.

Here is the log:

Wed Dec 13 00:14:30 2023 daemon.notice netifd: Interface ‘wgserver’ is setting up now
Wed Dec 13 00:14:30 2023 daemon.notice netifd: Interface ‘wgserver’ is now up
Wed Dec 13 00:14:30 2023 daemon.notice netifd: Network device ‘wgserver’ link is up
Wed Dec 13 00:14:30 2023 kern.info kernel: [ 26.728557] IPv6: ADDRCONF(NETDEV_UP): wgserver: link is not ready
Wed Dec 13 00:15:19 2023 user.notice mwan3[8192]: Execute ifup event on interface wgserver (wgserver)
Wed Dec 13 00:15:19 2023 user.notice mwan3[8192]: Starting tracker on interface wgserver (wgserver)
Wed Dec 13 00:15:23 2023 user.notice firewall: Reloading firewall due to ifup of wgserver (wgserver)

Your home isp router have function modem only?