## What was reported
Issue neondatabase/serverless#11 (closed, 17 comments): Hi I’m getting the following error in Cloudflare workers
```
A hanging Promise was canceled. This happens when the worker runtime is waiting for a Promise from JavaScript to resolve, but has detected that the Promise cannot possibly ever resolve because all code and events related to the Promise's I/O context have already finished. ✘ [ERROR] Uncaught (in response) Error: The script will never generate a response.
```
My code is simple
```
import { Client } from '@neondatabase/serverless'
import { Env } from './models'
export default {
async fetch(request: Request, env: Env
## The verified resolution
[jawj (maintainer)]: Do not keep a Pool/Client alive between requests on Cloudflare Workers - each invocation is isolated and the worker kills promises tied to a finished request's I/O context ('The script will never generate a response'). Create the Pool inside the fetch/request handler. Same symptom occurs locally when the connection string env var is undefined (put env vars in `.dev.vars` for `wrangler dev`), and newer driver versions surface connect errors more helpfully instead of hanging.