Troubleshooting Launch Response Error Codes

This guide helps you to quickly diagnose and resolve response errors in Contentstack Launch, whether they originate from the CDN edge layer or your backend serverless functions (the origin). For each issue, we provide the specific error message, a detailed explanation of its cause, and steps to resolve the issue.

Launch Response Error Codes

Error Codes from the CDN Edge

Internal Server Error CFL-0001

A CDN edge error occurs when the request reaches the CDN layer, but the Launch Edge Function fails to execute correctly. This error returns a 500 response.

Cause:
The Edge Function encountered an unhandled exception or returned an invalid or malformed response.

Resolution:

• Check the Launch Server Logs associated with the Edge Function’s execution to identify what caused the failure.
• Review the Edge Function’s logic to ensure there are no unhandled exceptions.
• Ensure the function always returns a valid, properly structured response.

Error Codes from the Origin

Origin errors occur when a request reaches your backend serverless functions, but an issue prevents them from processing the request or returning a valid response.

Internal Server Error CF001

Error:
Internal Server Error CF001: The server failed to start. Check the Launch Server logs for details.

Launch attempted to start your project’s server, but the process failed to initialize. This error returns a 500 response.

Cause:
An incorrect server command, missing or invalid build output, an unexpected error that prevents the server from starting, or an application crash caused by running out of memory.

Resolution:

• Check the Launch Server Logs or your configured Log Targets.
• Verify that the server command is correct and can start successfully in your local environment.
• Fix configuration or build issues and redeploy the project.

Internal Server Error CF002

Error:
Internal Server Error CF002: An internal error occurred. Try again, or contact Contentstack Support if the issue persists.

This error occurs when the Launch infrastructure encounters an unexpected issue while processing the request. It returns a 500 response.

Cause:
An unexpected issue within the Launch platform prevented the request from completing successfully.

Resolution:

• Retry the request after a short period.
• If the issue persists, contact Contentstack Support and include relevant logs or request details for further investigation.

Bad Gateway CF003

Error:
Bad Gateway CF003: The total size of the response headers exceeded the limit. Check and reduce their size.

Your server-side application returned response headers whose combined size was greater than the allowed limit. This error returns a 502 response.

Cause:

• Large cookies.
• Too many Set-Cookie headers.
• Oversized custom headers (tokens, metadata, etc.).

Resolution:

• Reduce the overall size of your response headers.
• Minimize or remove large cookies.
• Review and optimize custom headers to ensure they remain within supported limits.

Internal Server Error CF004

Error:
Internal Server Error CF004: No valid response from the server. Check the Launch Server Logs and try again.

This error occurs when the origin function executes but does not return a valid HTTP response. It returns a 500 response.

Cause:

• Failure to fetch data from external sources.
• Runtime errors that prevented the response from being generated.

Resolution:

• Review the Launch Server Logs or your configured Log Targets to identify the failure.
• Ensure the application always returns a valid HTTP response, including status code, headers, and body.
• Fix the underlying issue and redeploy the project.

Request Body Exceeds Size Limit CF1001

Error:
The request body exceeds the maximum allowed size of 5 MB.

This error occurs when a request sent to Launch contains a payload whose total size exceeds the maximum supported limit of 5 MB. Launch enforces a strict request body size limit of 5 MB at the origin layer. This error returns a 413 response.

Cause:

• Uploading large request payloads in a single API call.
• Sending large JSON bodies with excessive or unnecessary data.
• Including embedded files, base64-encoded content, or large configuration objects in the request body.
• Incorrect usage of APIs that expect references (such as signed URLs) instead of raw file content.

Resolution:

• Ensure the total request body size is within 5 MB.
• Remove unnecessary fields or data from the request payload.
• Use supported file upload workflows (such as signed upload URLs) instead of sending files directly in the request body.
• Split large payloads into smaller, supported requests where applicable.
• Retry the request after reducing the payload size.

Bad Gateway CF1003

Error:
The request failed due to incorrect usage of path or query parameters. Refer to RFC 3986 to verify whether the path or query parameters are valid. Contact Contentstack Support if the path or query parameters are correct.

This error occurs when the request reaches the Launch origin layer and the path or query parameters are not formatted according to defined URL standards. As a result, the upstream service cannot process the request. This error returns a 502 response.

Cause:

• Invalid or malformed URL paths.
• Incorrectly encoded query parameters.
• Unsupported or unexpected characters in the path or query string.
• Improper use of reserved characters (such as spaces, #, %, or ?) without proper encoding.
• Requests that do not conform to URL formatting rules defined in RFC 3986.

Resolution:

• Verify that the request path and query parameters are correctly formatted and URL-encoded.
• Ensure the URL complies with the standards defined in RFC 3986.
• Check for unsupported or unescaped special characters in the path or query string.
• Retry the request after correcting the URL format.
• If the path or query parameters are valid and the issue persists, contact Contentstack Support with request details for further investigation.