Making atlassian-connect-express work with Next.js

I’m making a boilerplate project for creating Atlassian Add-ons with Next.js.

I’ve customized the server.js file of my Next.js project to match atlassian-connect-express, but when I run it, the get request for the atlassian-connect-express.json file returns status 404.

Any idea how I can wire this up?

The project can be found here.