Error 1013

Error 1013: HTTP hostname and TLS SNI hostname mismatch

This error indicates a mismatch between the HTTP hostname and the TLS SNI hostname.

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:

• A HAR file captured while duplicating the error.