Error 1101 indicates that a Cloudflare Worker (serverless JavaScript running at the edge) assigned to this route encountered an unhandled exception during execution. The Worker started but crashed before it could return a response. This is a server-side code error in the Worker script itself — it is the Cloudflare Workers equivalent of a 500 Internal Server Error. The site owner needs to debug and fix the Worker code.
The Worker script has a JavaScript error (TypeError, ReferenceError, etc.) that is not caught by a try-catch block, causing the Worker to crash.
The Worker hit Cloudflare's CPU time limit (10ms for free, 30ms for bundled, more for unbound), memory limit, or subrequest limit, causing it to be terminated.
The Worker makes a fetch() call to an external service that fails, and the error is not properly handled in the code.
Use 'wrangler tail' to stream real-time Worker logs and see the exact exception message and stack trace.
wrangler tail --format pretty
Wrap your Worker's fetch handler in a try-catch block that returns a meaningful error response instead of crashing.
Use 'wrangler dev' to run the Worker locally and reproduce the error with the same request that caused the 1101.
wrangler dev
Review your Worker's CPU time and memory usage in the Cloudflare dashboard under Workers > your-worker > Analytics. If hitting limits, optimize the code or upgrade to Workers Unbound.
A Cloudflare Worker exceeded the maximum number of subrequests (fetch calls) allowed per invocation.
Cloudflare received an empty, unknown, or unexpected response from the origin server.
The origin web server refused or is not accepting connections from Cloudflare.