Messages For Web (messages.google.com) Not Working

I usually keep a browser tab open at https://messages.google.com for reading/responding to text messages more easily from my computer.

But today, it just stopped working, and just shows a blank gray page after the initial "animation."

I looked at my browser cookies, and there are none specifically from "messages.google.com" (and I don't really want to bulk delete all my .google.com cookies!)

It does appear to work if I try to pair it fresh with an incognito browser window, so it is probably cookie related. I hope they can fix this without me having to delete all my google cookies, or go manually through them editing....