Hi Fly team,
I’m running a Cloudflare Worker that calls my Fly app’s gRPC endpoint at https://*.fly.dev. The domain is the standard *.fly.dev subdomain—not
proxied through Cloudflare on my side.
The Worker consistently gets HTTP 409 responses. Logs inside the Worker show headers like:
gRPC request failed: HTTP 409 fly-request-id= cf-ray=99e3582173f7e004-LAX server=cloudflare
via=
Notably:
-
Every failing response has server=cloudflare and a cf-ray, but no fly-request-id, which means the
request never reaches my Fly app.
-
The exact same request (same headers, same path) works fine from a browser or curl on my local machine;
only the Cloudflare Worker is blocked.
-
It looks like Cloudflare Worker traffic hits Fly’s Cloudflare front door from a Cloudflare/Workers IP
range and is rejected with 409 before Fly Router processes it.
Could someone from Fly confirm whether there’s a protection rule blocking Cloudflare Workers’ egress
IPs? If so, can it be relaxed or is there a recommended workaround (e.g., an officially supported way
for Cloudflare Workers to reach Fly apps without being rejected)? I can provide timestamp/cf-ray samples
if needed.
Thanks!