Relative module was not found in Vue.js when build project

If you installed your nuxt project using Yarn try deleting the node_modules and then installing using npm i instead. There are some hooks that will not be run by yarn when installing your dependencies for nuxt.

It was a spelling error. I changed

import App from './app.vue';

to

import App from './App.vue';

and it fix the error. Thanx to Derek for help

It could also be, because your node_modules, is not at the root of the project.