Hi @oreid,
I was having the same issue and I’ve tracked it down to a breaking change in the rw-server package, so in your ./fly/start.sh you’re pulling the breaking change with your npx rw-server call.
Unfortunately rw-server is still in experimental status, so there can be breaking changes introduced there, for stability it might be best to use the cli yarn rw serve api - I’m not familiar with fly so I’m not sure about what the best approach would be to call that command from the start script.
If the script has access to the node_modules folder you could call
./node_modules/.bin/redwood serve api --port 8910
to use the serve command that will be pinned to whatever redwoodjs version your app is running, or if for whatever reason you need to call it remotely you can use
npx redwood serve api --port 8910