Troubleshooting Error 1016 - Origin DNS error

The most common causes of error 1016 are:

Main reason : Error 1016 indicates that Cloudflare cannot send a request to your server, because its original IP cannot be resolved via DNS.

1. DNS Configuration Cloudflare does not have a DNS record that matches the original IP address.
2. You have a DNS CNAME record pointing to an external domain.
3. You are using Cloudflare Load Balancer and root hostname (CNAME) in the default zone, and the backup group is not resolved via DNS (Use backup group configured with root IP as backup in all case other groups are not available)

overview

Cloudflare returns error 1016 when the original server IP cannot be found.

Common causes of error 1016

The most common cause for error 1016 is:

1. Configure a user's DNS Cloudflare without DNS records matching the original IP address.
2. You have a DNS CNAME record that points to an external domain and that domain cannot be resolved.
3. You are using Cloudflare Load Balancer and the root server name (CNAME) in the default zone / zone and the backup pool cannot be resolved via DNS. Using a backup pool is configured with the original IP as a backup in case all other pools are not available.

Remote servers that are overused or have a geographical distance too far will add unnecessary latency and affect the visitor's experience. In many cases, untrusted servers or misconfigured servers will prevent the visitor's request completely, blocking access to the web, web application, or API. A poor experience for visitors like this has a direct impact on sales, reputation and customer loyalty.

Expanding on the available DNS infrastructure of Cloudflare and the global Anycast network, Cloudflare Load Balancing solves these problems by providing:

1. Local and global load balancing to reduce latency by load balancing traffic on multiple servers or by routing traffic to the nearest location.
2. Check failover to quickly route visitors to avoid errors.

Troubleshooting Error 1016 - Origin DNS error

To resolve error 106, make sure the original IP address can resolve through DNS. You can try the following:

1. Verify that your DNS Cloudflare settings include A records that point to a valid IP address. You can edit an existing A record or create a new record.

2. For a CNAME record to point to an external domain, ensure that the destination domain can be resolved. See the section below for help verifying the DNS resolution of the external record.

Verify the DNS resolution of the external record

You can use some command line tools as well as third-party tools to check DNS resolution.

dig

 dig something.anotherdomain.com dig +trace something.anotherdomain.com dig something.anotherdomain.com @1.1.1.1 

The + trace option outputs detailed information when a DNS response fails. This information may be useful when working with DNS providers to troubleshoot.

Option @ 1.1.1.1 returns results from Cloudflare's public DNS resolver. This is useful in confirming whether public resolvers can receive DNS responses.

nslookup

 nslookup something.anotherdomain.com nslookup something.anotherdomain.com 1.1.1.1 

Option @ 1.1.1.1 returns results from Cloudflare's public DNS resolver. This is useful in confirming whether public resolvers can receive DNS responses.

Third-party tools

Some online services, such as whatsmydns.net, check DNS resolution worldwide.

A response other than a valid IP address (for example, timeout, SERVFAIL, NXDOMAIN or NOERROR) most likely causes your problem. To resolve, contact your DNS provider for CNAME.

See more:

1. How to fix 401 Unauthorized error
2. How to fix 403 Forbidden Error
3. How to fix 'The 504 Gateway Timeout' error