HTTP/5xx (Server Error)
523 Origin Is Unreachable
Cloudflare-specific: Cloudflare could not reach the origin server at all.
❓ Why does this happen?
Incorrect DNS records or routing issues between Cloudflare and the origin network.
✅ How to fix it
Fix the origin IP in Cloudflare DNS settings and test with: curl -v --resolve example.com:443:ORIGIN_IP https://example.com
Return or handle 523 in your stack
// Note: 523 is normally generated by Cloudflare, not your app.
// Emitting it yourself is only useful for testing client error handling.
// app/api/resource/route.ts
export function GET() {
return Response.json(
{ error: "Origin Is Unreachable", status: 523 },
{
status: 523
}
);
}Live 523 mock endpoint
Point your app, tests, or retry logic at this free public URL to reproduce a real 523 response (CORS enabled, optional ?delay=ms up to 5000).
https://castov.com/api/mock/523Frequently Asked Questions
What does HTTP Status 523 mean?
Why am I getting a 523 status code?
How do I fix a 523 Origin Is Unreachable error?
How can I test how my app handles a 523 response?
Other 5xx status codes
Browse the full HTTP status codes directory or troubleshoot terminal errors in the Error Fix Encyclopedia.