Troubleshooting Cloudflare 1XXX errors

Diagnose and resolve 1XXX errors for Cloudflare proxied sites.


Overview

The errors described in this document might occur when visiting a website proxied by Cloudflare. For Cloudflare API or dashboard errors, review our Cloudflare API documentation. HTTP 409, 530, 403, 429 errors are the HTTP error codes returned in the HTTP status header for a response. 1XXX errors appear in the HTML body of the response.

Cloudflare Custom Error Pages allows customers to change the appearance of the default error pages discussed in this article.

If the resolutions within each error description below do not resolve the error, contact Cloudflare Support.

Only the site owner may contact Cloudflare for technical support. Lookup contact information for a domain via the Whois database.

Error 1000: DNS points to prohibited IP

Common causes

Cloudflare halted the request for one of the following reasons:

  • An A record within your Cloudflare DNS app points to a Cloudflare IP address.
  • Your Cloudflare DNS A or CNAME record references another reverse proxy (such as an nginx web server that uses the proxy_pass function) that then proxies the request to Cloudflare a second time.
  • The request X-Forwarded-For header is longer than 100 characters.
  • The request includes two X-Forwarded-For headers.

Resolution

  • If an A record within your Cloudflare DNS app points to a Cloudflare IP address, update the IP address to your origin web server IP address.
  • There is a reverse-proxy at your origin that sends the request back through the Cloudflare proxy. Instead of using a reverse-proxy, contact your hosting provider or site administrator to configure an HTTP redirect at your origin.

Error 1001: DNS resolution error

Common causes

  • A web request was sent to a Cloudflare IP address for a non-existent Cloudflare domain.
  • The target of the DNS CNAME record does not resolve.
  • A CNAME record in your Cloudflare DNS app requires resolution via a DNS provider that is currently offline.

Resolution

A non-Cloudflare domain cannot CNAME to a Cloudflare domain unless the non-Cloudflare domain is added to a Cloudflare account.

Attempting to directly access DNS records used for Cloudflare CNAME setups also causes error 1001 (For example: www.example.com.cdn.cloudflare.net).


Error 1002: DNS points to Prohibited IP

Common causes

  • A DNS record in your Cloudflare DNS app points to one of Cloudflare's IP addresses.
  • An incorrect target is specified for a CNAME record in your Cloudflare DNS app.
  • Your domain is not on Cloudflare but has a CNAME that refers to a Cloudflare domain.

Resolution

Update your Cloudflare A or CNAME record to point to your origin IP address instead of a Cloudflare IP address:

  1. Contact your hosting provider to confirm your origin IP address or CNAME record target.
  2. Log in to your Cloudflare account.
  3. Select the domain that generates error 1002.
  4. Select the DNS app.
  5. Click on the Value field for the A record to update.
  6. Update the A record.

To ensure your origin web server doesn’t proxy its own requests through Cloudflare, configure your origin web server to resolve your Cloudflare domain to:

  • The internal NAT’d IP address, or
  • The public IP address of the origin web server.

Error 1002: Restricted

Common cause

The Cloudflare domain resolves to a local or disallowed IP address or an IP address not associated with the domain.

Resolution

If you own the website:

  1. Confirm your origin web server IP addresses with your hosting provider,
  2. Log in to your Cloudflare account, and
  3. Update the A records in the Cloudflare DNS app to the IP address confirmed by your hosting provider.

Error 1003 Access Denied: Direct IP Access Not Allowed

Common cause

A client or browser directly accesses a Cloudflare IP address.

Resolution

Browse to the website domain name in your URL instead of the Cloudflare IP address.


Error 1004: Host Not Configured to Serve Web Traffic

Common causes

  • Cloudflare staff disabled proxying for the domain due to abuse or terms of service violations.
  • DNS changes have not yet propagated or the site owner’s DNS A records point to Cloudflare IP addresses.

Resolution

If the issue persists beyond 5 minutes, contact Cloudflare Support.


Errors 1006, 1007 or 1008 Access Denied: Your IP address has been banned

Common causes

A Cloudflare customer blocked traffic from your client or browser.

Error also 1006 occurs in the Cloudflare Workers app under the Preview tab when a customer uses Zone Lockdown or any other Cloudflare security feature to block the Google Cloud Platform IPs that the Preview tab relies upon.

Resolution

Request the website owner to investigate their Cloudflare security settings or whitelist your client IP address. Since the website owner blocked your request, Cloudflare support cannot override a customer’s security settings.


Error 1010: The owner of this website has banned your access based on your browser's signature

Common cause

A website owner blocked
your request based on your client's web browser.

Resolution

Notify the website owner of the blocking. If you cannot determine how to contact the website owner, lookup contact information for the domain via the Whois database. Site owners disable Browser Integrity Check via the Settings tab of the Firewall app.

Since the website owner performed the blocking, Cloudflare support cannot override a customer’s security settings.

Error 1011: Access Denied (Hotlinking Denied)

Common cause

A request is made for a resource that uses Cloudflare hotlink protection.

Resolution

Notify the website owner of the blocking. If you cannot determine how to contact the website owner, lookup contact information for the domain via the Whois database.  Hotlink Protection is managed via the Cloudflare Scrape Shield app.

Since the website owner performed the blocking, Cloudflare support cannot override a customer’s security settings.

Error 1012: Access Denied

Common cause

A website owner forbids access based on malicious activity detected from the visitor’s computer or network (ip_address). The most likely cause is a virus or malware infection on the visitor’s computer.

Resolution

Update your antivirus software and run a full system scan. Cloudflare can not override the security settings the site owner has set for the domain. To request website access, contact the site owner to whitelist your IP address. If you cannot determine how to contact the website owner, lookup contact information for the domain via the Whois database.

Since the website owner performed the blocking, Cloudflare support cannot override a customer’s security settings.

Error 1013: HTTP hostname and TLS SNI hostname mismatch

Common cause

The hostname sent by the client or browser via Server Name Indication (SNI) does not match the request host header.

Resolution

Error 1013 is commonly caused by the following:

  • your local browser setting the incorrect SNI host header, or
  • a network proxying SSL traffic caused a mismatch between SNI and the Host header of the request.

Test for an SNI mismatch via an online tool such as: SSL Shopper.

Provide Cloudflare Support the following information:

  1. A HAR file captured while duplicating the error

Error 1014: CNAME Cross-User Banned

Common cause

By default, Cloudflare prohibits a DNS CNAME record between domains in different Cloudflare accounts. CNAME records are permitted within a domain (www.example.com CNAME to api.example.com) and across zones within the same user account (www.example.com CNAME to www.example.net).

Resolution

Allow CNAME records across accounts for domains on Cloudflare Pro, Business, or Enterprise plans by contacting Cloudflare support.


Error 1015: You are being rate limited

Common cause

The site owner implemented Rate Limiting that affects your visitor traffic.

Unable to purge is another 1015 error code relating to Cloudflare cache purge. Retry the cache purge and contact Cloudflare support if errors persist.

Resolution

  • If you are a site visitor, contact the site owner to request exclusion of your IP from rate limiting.
  • If you are the site owner, review Cloudflare Rate Limiting thresholds and adjust your Rate Limiting configuration.
If your Rate Limiting blocks requests in a short time period such as 1 second, try increasing the time period to 10 seconds.
If you expect a new Cloudflare Worker to exceed rate limits, refer to the Workers documentation for guidance.

Error 1016: Origin DNS error

Common cause

Cloudflare cannot resolve the origin web server’s IP address.

Common causes for Error 1016 are:

  • A missing DNS A record that mentions the origin IP address.
  • A CNAME record in Cloudflare DNS points to an unresolvable external domain.
  • The origin host names (CNAMEs) in your Cloudflare Load Balancer default, region, and fallback pools are unresolvable. Use a fallback pool configured with an origin IP as a backup in case all other pools are unavailable.

Resolution

To resolve error 1016:

  1. Verify your Cloudflare DNS settings include an A record that points to a valid IP address that resolves via a DNS lookup tool.
  2. For a CNAME record pointing to a different domain, ensure that the target domain resolves via a DNS lookup tool.

Error 1018: Could not find host

Common causes

  • The Cloudflare domain was recently activated and there is a delay propagating the domain’s settings to the Cloudflare edge network
  • The Cloudflare domain was created via a Cloudflare partner (e.g., a hosting provider) and the provider's DNS failed
Error 1018 is returned via a HTTP 409 response code.

Resolution

Contact Cloudflare Support with the following details:

  1. Your domain name
  2. A screenshot of the 1018 error including the RayID mentioned in the error message
  3. The time and timezone the 1018 error occurred

Error 1019: Compute server error

Common cause

A Cloudflare Worker script recursively references itself.

Resolution

Ensure your Cloudflare Worker does not access a URL that calls the same Workers script.


Error 1020: Access denied

Common cause

A client or browser is blocked by a Cloudflare customer’s Firewall Rules.

Resolution

If you are not the website owner, provide the website owner with a screenshot of the 1020 error message you received.

If you are the website owner:

  1. Retrieve a screenshot of the 1020 error from your customer
  2. Search the Firewall Events Log within the Overview tab of your Cloudflare Firewall app for the RayID or client IP Address from the visitor’s 1020 error message.
Convert the UTC timestamp of the 1020 error to your local timezone when searching in the Firewall Events Log.
  1. Assess the cause of the block and either update the Firewall Rule or whitelist the visitor’s IP address in IP Access Rules.

Error 1025: Please check back later

Common cause

A request is not serviced because the domain has reached plan limits for Cloudflare Workers.

Resolution:

Purchase a paid Workers subscription via the Upgrade Workers Plan button in the Cloudflare Workers app.


Error 1101: Rendering error

Common cause

A Cloudflare Worker throws a runtime JavaScript exception.

Resolution:

Provide appropriate issues details to Cloudflare Support.


Error 1102: Rendering error

Common cause

A Cloudflare Worker exceeds a CPU time limit. CPU time is the time spent executing code (for example, loops, parsing JSON, etc). Time spent on network requests (fetching, responding) does not count towards CPU time.

Resolution

Contact the developer of your Workers code to optimize code for a reduction in CPU usage in the active Workers scripts.


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