527 Railgun Error

527

Railgun Error

Example HTTP Response

HTTP Response

HTTP/1.1 527 Railgun Listener Error
Server: cloudflare
Content-Type: text/html

<html><body>Error 527: Railgun Listener error</body></html>

Common Causes

Railgun listener not responding
Railgun service crashed or stopped on origin
Firewall blocking Railgun connection (port 2408)
Railgun listener timeout
Railgun software misconfigured
Origin server resources exhausted affecting Railgun
Network issues between Cloudflare and Railgun listener

Technical Details

What does this mean?

The express train broke down! Cloudflare tried to use the super-fast Railgun connection to your origin but the rail line is having issues. Time to call maintenance!

Technical Definition

The request failed after Cloudflare established a connection to the origin Railgun server. Railgun is Cloudflare's deprecated WAN optimization technology.

Code Snippets

Ready-to-use code for returning this HTTP status in your application:

Node.js

// Express.js
app.get('/example', (req, res) => {
  res.status(527).json({
    error: 'Railgun Error',
    message: 'Your error message here'
  });
});

// Native HTTP
const http = require('http');

http.createServer((req, res) => {
  res.writeHead(527, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify({
    error: 'Railgun Error',
    message: 'Your error message here'
  }));
}).listen(3000);

Related Status Codes

⏱️522Connection Timed Out 🚫521Web Server Is Down

527 Railgun Error FAQ

What causes a 527 Railgun Error error?

Railgun listener not responding. Railgun service crashed or stopped on origin. Firewall blocking Railgun connection (port 2408). Railgun listener timeout. Railgun software misconfigured. Origin server resources exhausted affecting Railgun. Network issues between Cloudflare and Railgun listener.

// Express.js app.get('/example', (req, res) => { res.status(527).json({ error: 'Railgun Error', message: 'Your error message here' }); }); // Native HTTP const http = require('http'); http.createServer((req, res) => { res.writeHead(527, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: 'Railgun Error', message: 'Your error message here' })); }).listen(3000);

527 Railgun Error FAQ

What causes a 527 Railgun Error error?