Express server accessible by REST client & Edge but not Chrome

I’ve been trying to get a Node/Express/Prisma app deployed to

I can deploy the app, see the Express server start, and health checks pass upon deployment.

However the server does not respond to visiting the URL for the app, eventually resulting in a 503 error.

The server responds when run locally. I have checked the internal port configuration, worked through the troubleshooting steps and I’m out of ideas!

Things that might be unusual:

  • I’m running the server using tsx
  • I’ve specified 18.16.1-bullseye-slim as my base image (to match my local node version. Bullseye was required to get python dependency)
  • I had to change the import statement in docker-entrypoint.js to a CommonJS import because I was getting errors that I could not import ES6 packages outside a module
  • I am developing on Windows

flyctl services list

TCP             80 => 3000      [HTTP]          True            app             sin     1
TCP             443 => 3000     [HTTP,TLS]      False           app             sin     1


app = "app-api"
primary_region = "sin"
  dockerfile = "./docker/Dockerfile"
  ignorefile = "./docker/.dockerignore"

  internal_port = 3000
  force_https = true
  auto_stop_machines = true
  auto_start_machines = true
  min_machines_running = 0

    grace_period = "10s"
    interval = "30s"
    method = "GET"
    timeout = "5s"
    path = "/signin/google/success"


# syntax = docker/dockerfile:1

# Adjust NODE_VERSION as desired
FROM node:${NODE_VERSION}-bullseye-slim as base

LABEL fly_launch_runtime="Node.js/Prisma"

# Node.js/Prisma app lives here

# Set production environment
ENV NODE_ENV=production

# Throw-away build stage to reduce size of final image
FROM base as build

# Install packages needed to build node modules
RUN apt-get update -qq && \
    apt-get install -y python pkg-config build-essential openssl 

# Install node modules
COPY --link package.json yarn.lock ./
RUN yarn install --frozen-lockfile --production=false

# Generate Prisma Client
COPY --link prisma .
RUN npx prisma generate

# Copy application code
COPY --link . .

# Remove development dependencies
RUN yarn install --production=true

# Final stage for app image
FROM base

# Install packages needed for deployment
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y openssl && \
    rm -rf /var/lib/apt/lists /var/cache/apt/archives

# Copy built application
COPY --from=build /app /app

# Entrypoint prepares the database.
ENTRYPOINT [ "/app/docker/docker-entrypoint.js" ]

# Start the server by default, this can be overwritten at runtime
CMD [ "yarn", "run", "start" ]


#!/usr/bin/env node
const spawn = require("node:child_process").spawn;

const env = { ...process.env };

(async () => {
  // If running the web server then migrate existing database
  if (process.argv.slice(2).join(" ") === "yarn run start") {
    await exec("npx prisma migrate deploy");

  // launch application
  await exec(process.argv.slice(2).join(" "));

function exec(command) {
  const child = spawn(command, { shell: true, stdio: "inherit", env });
  return new Promise((resolve, reject) => {
    child.on("exit", (code) => {
      if (code === 0) {
      } else {
        reject(new Error(`${command} failed rc=${code}`));


"use strict";
import express from "express";

const app = express();
const port = process.env.PORT || 3000;
app.get("/signin/google/success", (req, res) => {
// Start server
app.listen(port, "::", () =>
  console.log(`🚀 Server ready, listening on port ${port}`)

Start command

npx tsx server.js

An update. Using this path to the app:

  • A REST client gets a 200 OK response
  • Microsoft EDGE gets a 200 OK response
  • Chrome times out with a 503 response

Anyone know what’s going on?

Strange issue!

Have you tested Chrome on another device, or in Incognito Mode?

It mysteriously resolved after I cleared the (empty) cookies for the site, prompted by this: Clearing browser cookies fixes "could not find an instance to route to" 503 error

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