Shopify App (Node.js) redirect urls not working

Hi everyone. I recently built a Shopify app and tried deploying it following Shopify’s own documentation. It doesn’t work for me. The app does get launched, I don’t get errors on deployment, but when I try calling any routes besides the main url, I get all kinds of errors. The exact same code works on Heroku btw! See my Stackoverflow post for the exact issue. Help would be HIGHLY appreciated

When you say “The app works with all the callbacks working with a ngrok tunnel during development.” what url did you register as the call back? It’s probably not the same as your new url. Maybe you just need to change your oauth app’s callback’s on their dashboard or make a new app called “fly production” vs. the one you were using before for local dev with ngrok?

I replace the callback url’s in shopify’s app dashboard with the fly app urls as shown in the Shopify documentation. That’s also how I get it working with Heroku. So that’s not it.

That is, unless I have to redirect to specific other urls which aren’t mentioned in the Shopify documentation nor applicable to Heroku/ngrok