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Cloudflare Error Codes: 520–526, 1015, 1020

Cloudflare shows its own error pages when it can't get a good response from a website's server, or when a rule blocks you. Here's what each code means.

Cloudflare error 5xx / 1xxx

5xx codes mean Cloudflare couldn't get a proper answer from the website's own server. 1xxx codes mean a Cloudflare rule or service stopped your request.

Quick checks

  • Note the code and the Ray ID at the bottom of the error page.
  • 5xx: the site's server has a problem; wait or contact the site.
  • 1015 or 1020: you were rate limited or blocked; slow down, turn off the VPN, or contact the site.

If you’re visiting the site

  1. What each code means for you

    1. 520–526: the website's server is failing behind Cloudflare. Nothing to fix on your side; try later.
    2. 1015 You are being rate limited: too many requests from your IP. Wait a few minutes.
    3. 1020 Access denied: a firewall rule blocked you, often by country, VPN or bot detection. Turn off the VPN or contact the site with the Ray ID.

If you run the site

  1. Origin errors

    1. 520 unknown error: empty or malformed origin response, crashes, oversized headers.
    2. 521 web server is down: the origin refused the connection; start it or allow Cloudflare's IPs.
    3. 522 connection timed out: no answer from the origin; check firewalls, load and the DNS record.
    4. 523 origin is unreachable: routing or DNS problem reaching the origin's IP.
    5. 524 a timeout occurred: the origin took over 100 seconds to respond.
    6. 525 SSL handshake failed: the origin's TLS setup doesn't work with Cloudflare (no SNI support, no shared cipher).
    7. 526 invalid SSL certificate: with Full (strict), the origin certificate is expired, self-signed or for the wrong name.

  2. Rule and platform errors

    1. 1015: a rate-limiting rule fired; adjust the threshold if real users hit it.
    2. 1020: a WAF custom rule blocked the request; find it in Security › Events with the Ray ID.
    3. 1101: a Cloudflare Worker threw a JavaScript exception; check the Worker's logs.

Still not working?

Owners: search the Ray ID in the Cloudflare dashboard (Security › Events for blocks), then check origin logs at that time. For origin errors, test the server directly with curl --resolve to bypass Cloudflare.

See what’s happening

LightAtom's connections view shows which Cloudflare edge addresses your Mac connects to, and the Map where they appear.

Frequently asked questions

What are Cloudflare 5xx errors?

Errors Cloudflare shows when the website's origin server fails: refused or timed-out connections, invalid responses, slow responses or TLS problems. The site's owner has to fix them.

What does Cloudflare error 1020 mean?

Access denied by a firewall rule the site set up, such as blocking countries, VPNs or suspicious traffic. Only the site can unblock you.

What does error 1015 mean?

You are being rate limited: your IP address sent more requests than the site's rule allows. Wait, and avoid reload loops or scripts.

What is a Ray ID?

A unique ID for your request, shown on Cloudflare error pages. Site owners use it to find the exact request in their logs.

Can I bypass a Cloudflare error?

No. Origin errors need the site to fix its server, and blocks are deliberate. A cached copy of the page, such as from a search engine, is the only workaround.

Related errors and tools

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LightAtom team

The people who build LightAtom, a network monitor for macOS.