Error Code Portal
CloudflareCloudflare HTTP errorsError code

1037

Error 1037: Invalid rewrite rule (failed to evaluate expression)

Alternative forms: Error 1037

What does this code mean?

Code 1037 · An issue reported by Cloudflare HTTP errors.

Official explanation · Original text

This error indicates that the rewrite rule expression could not be evaluated. There are several causes for this error, but it can mean that one expression element contained an undefined value when it was evaluated.

Troubleshooting and diagnostic links

First check that the document's product, version, and environment match your situation.

Source and terms of use

Error 1037: Invalid rewrite rule (failed to evaluate expression) ↗

Creator: Cloudflare, Inc. and contributors
License: Creative Commons Attribution 4.0 International
Checked on: 2026-11-12

Modifications: Selected introductory official description; Markdown stripped; original Korean product context added. Direct official error page retains the complete cause and resolution instructions.

Source details · Original licenses and notices