VSCode doesn't show missing references

Question

I have a NextJS project in which VSCode doesn't give an error when a file is missing (ie importing stuff from a file that doesn't exist). How do I fix this ? It doesn't show an error when I call a function that doesn't exist either.

Here is my ESLint config for reference.

env:
  browser: true
  es2021: true
  node: true
extends:
  - plugin:react/recommended
  - standard
parser: '@typescript-eslint/parser'
parserOptions:
  ecmaFeatures:
    jsx: true
  ecmaVersion: latest
  sourceType: module
plugins:
  - react
  - '@typescript-eslint'
rules: {
  no-use-before-define: "off",
  @typescript-eslint/no-use-before-define: ["error"]
}