Error 1016: Origin DNS error for

When I attempt to run my worker, I am given this error

How do I fix this? I’ve never seen this error before!

What’s your Worker code

addEventListener(“fetch”, (event) => {
(err) => new Response(err.stack, { status: 503 })


if (pathname.startsWith("/api")) {
return new Response(JSON.stringify({ pathname }), {
headers: { “Content-Type”: “application/json” },

if (pathname.startsWith("/status")) {
const httpStatusCode = Number(pathname.split("/")[2]);

return Number.isInteger(httpStatusCode)
  ? fetch("" + httpStatusCode)
  : new Response("That's not a valid HTTP status code.");


return fetch(“”);

I’m assuming you have replaced those URLs, if not, that’s why. They don’t resolve. If you have, please post the actual ones

Also, you can use codeblock

You mean change them to a different URL? Ok, will do!

Where do I add that (into the code)?

On the forums:
addEventListener(‘fetch’, …

will result in

addEventListener('fetch', ...

a code block. Code is readable that way

I changed the URL’S and now it’s returning a Chrome error 521

I added the code block and it’s still returning a 521 error! Do the changes take a few minutes to take effect?

That 521 is coming from the link you’re fetching.

That means that the web origin is down right? If not, then what the ■■■■ does it mean?

UPDATE: I have set Cloudflare IP’s to “Bypass” all features via my firewall rule settings! I have also created a Cloudflare client certificate
Unfortunately, I still get the error!