message: Listen only on IPv4 (avoid client IP sometimes being ipv6)
diff: @@ -134,7 +134,7 @@ db.then(async () => {
  console.error('An error occurred while setting up the blockchain event handlers', err)
  throw err
  }
  - app.listen(PORT, () => {
  + app.listen(Number(PORT), '0.0.0.0', () => {
  console.log(`Server is listening on ${PORT}\n`)
  });
  })
  