I keep on getting "Not Found" when I try to deploy my Svelte site to Netlify from Gitlab? Why?

Question

I have a Svelte site white is uploaded to Gitlab.

I tried to deploy it to Netlfiy but I keep on getting the notification "Not Found" after I enter the build settings and select "Deploy site".

Below are my svelte.config.js and netlify.toml files:

svelte.config.js:

import adapter from '@sveltejs/adapter-netlify';

export default {
    kit: {
        adapter: adapter({
            // if true, will split your app into multiple functions
            // instead of creating a single one for the entire app
            split: false
        })
    }
};

netlify.toml:

[build]
  command = "npm run build"
  publish = "build"

[context.production]
  environment = { NODE_VERSION = "16.6.0" }

Why isn't it working?