It's suppposed to mean that the server doesn't support any of the formats the client specified in the Accept* headers. At least for the main Accept header, browsers typically include */* and even if they don't the server is better off just pushing whatever so yeah, would be interesting to know why they chose to return that particular error here.
The eng team was extremely confused about what had broken our webflow setup (we do some magic with Cloudflare workers to point our marketing pages at at Webflow with a custom domain)... and then I saw that we were frontpage.
https://webcache.googleusercontent.com/search?q=cache:https:...