Worker's fetch is blocked by cloudflare

Tried fetching the root “/” of my site (which works when I access it directly from the browser) and I still get the 502 (Bad Gateway) status code in the worker. When I fetch another website that’s not fronted by Cloudflare (e.g. it works as expected, so it only seems to fail when hitting sites fronted by Cloudflare, thus why I think it blocks itself