We want to set up Fastly on the edge of a site hosted on Cloudflare Pages

We host our site on Cloudflare Pages. We want to set up Fastly on the edge of this site and have finished setting up the backend and override host on the Fastly side, but Cloudflare seems to be refusing to connect. The browser shows “Error 503 Max restarts limit reached” (Fastly error).

Does Cloudflare Pages not allow Fastly to be configured for edge?

EXAMPLE: Our site is “example.com”. The edge of this domain is configured with Fastly, and the backend is “example.pages.dev” (hosted by Cloudflare Pages). We are configuring the host to override “example.pages.dev” in Fastly settings.