basic google analytics pageview not working

I have a pretty basic setup, just installed the plugin to replace my legacy UA script. I wanted to just use gtm for everything, including legacy UA tag. I activated the plugin, setup my gtm id, created a new tag on gtm for google analytics pageview with the right settings. I can preview/debug and see the tag firing and a real time pageview event on my GA realtime dashboard. All working find end to end when I’m under preview/debug.

But the live site doesn’t work. Somewhere in this relay from: my page -> gtm collector -> ga collector, the event is getting dropped.

I’m stumped. Any idea how to debug this further?