Converting ring alarm pro to primary router shows no network connection

I have an existing setup with cable modem → Google wifi → Ring Alarm Pro. The Google Wifi is no longer supported, so I’d like to replace it with the Ring Alarm Pro (Cable modem → Ring).When I do this, the eero app reports that there’s no wired connection and the wifi icon on the ring goes red.I’ve restarted the ring alarm pro and cable modem without any change.I know the cables work because they work in the existing setup.I checked for some kind of mac filtering or something, but there are basically no options in the cable modem GUI.I’ve seen lots of posts about the Ring Alarm pro working as a router, so it seems like this should be possible. Am I missing something?