---
description: Troubleshoot Cloudflare 1101 error code.
title: Error 1101
image: https://developers.cloudflare.com/og-docs.png
---

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# Error 1101

Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-1xxx-errors/error-1101/index.md)|[Agent setup](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/agent-setup/)

## Error 1101: Rendering error

This error indicates a rendering issue.

### Common cause

This error typically occurs when a Cloudflare Worker encounters a runtime JavaScript exception.

### Debugging

To identify the specific JavaScript exception:

1. Check your Workers logs in the Cloudflare dashboard under **Workers & Pages** \> **Your Worker** \> **Logs**.
2. Review the Workers code for potential runtime errors such as:  
  * Undefined variables or functions
  * Type errors
  * Promise rejections
  * Network request failures
3. Test the [Worker locally](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/workers/local-development/#local-development) with sample requests to reproduce the error.
4. Refer to [Workers error handling](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/workers/observability/errors/) for more details on debugging Workers.

### Resolution

Fix the JavaScript exception in your Workers code. If you need assistance, [provide appropriate issue details](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/support/contacting-cloudflare-support/) to Cloudflare Support, including:

* The Ray ID from the error page
* The Worker name
* Recent changes to the Worker code
* Steps to reproduce the error

### Related errors

* [Error 1102](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-1xxx-errors/error-1102/) \- Workers CPU time limit exceeded
* [Error 500](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-500/) \- Internal server error (can be caused by Workers exceptions)

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