Ubuntu – 404 error on deploying Next.js app with GitHub Actions

I’m currently trying to deploy a Next.js app on GitHub Pages using GitHub Actions, but I get a page 404 error even after it successfully deploys. I’ve looked around a bunch of similarly named questions and am having trouble figuring this out.

Here is my GitHub repo: https://github.com/Mctripp10/mctripp10.github.io

Here is my website: https://mctripp10.github.io

I used the Deploy Next.js site to Pages workflow that GitHub provides. Here is the nextjs.yml file:

# Sample workflow for building and deploying a Next.js site to GitHub Pages
#
# To get started with Next.js see: https://nextjs.org/docs/getting-started
#
name: Deploy Next.js site to Pages

on:
  # Runs on pushes targeting the default branch
  push:
    branches: ["dev"]

  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:

# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
permissions:
  contents: read
  pages: write
  id-token: write

# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
concurrency:
  group: "pages"
  cancel-in-progress: false

jobs:
  # Build job
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Detect package manager
        id: detect-package-manager
        run: |
          if [ -f "${{ github.workspace }}/yarn.lock" ]; then
            echo "manager=yarn" >> $GITHUB_OUTPUT
            echo "command=install" >> $GITHUB_OUTPUT
            echo "runner=yarn" >> $GITHUB_OUTPUT
            exit 0
          elif [ -f "${{ github.workspace }}/package.json" ]; then
            echo "manager=npm" >> $GITHUB_OUTPUT
            echo "command=ci" >> $GITHUB_OUTPUT
            echo "runner=npx --no-install" >> $GITHUB_OUTPUT
            exit 0
          else
            echo "Unable to determine package manager"
            exit 1
          fi
      - name: Setup Node
        uses: actions/setup-node@v4
        with:
          node-version: "20"
          cache: ${{ steps.detect-package-manager.outputs.manager }}
      - name: Setup Pages
        uses: actions/configure-pages@v4
        with:
          # Automatically inject basePath in your Next.js configuration file and disable
          # server side image optimization (https://nextjs.org/docs/api-reference/next/image#unoptimized).
          #
          # You may remove this line if you want to manage the configuration yourself.
          static_site_generator: next
      - name: Restore cache
        uses: actions/cache@v4
        with:
          path: |
            .next/cache
          # Generate a new cache whenever packages or source files change.
          key: ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock') }}-${{ hashFiles('**.[jt]s', '**.[jt]sx') }}
          # If source files changed but packages didn't, rebuild from a prior cache.
          restore-keys: |
            ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock') }}-
      - name: Install dependencies
        run: ${{ steps.detect-package-manager.outputs.manager }} ${{ steps.detect-package-manager.outputs.command }}
      - name: Build with Next.js
        run: ${{ steps.detect-package-manager.outputs.runner }} next build
      - name: Static HTML export with Next.js
        run: ${{ steps.detect-package-manager.outputs.runner }} next export
      - name: Upload artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: ./out

  # Deployment job
  deploy:
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    runs-on: ubuntu-latest
    needs: build
    steps:
      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4

I got this on the build step:

Route (app)                              Size     First Load JS
┌ ○ /_not-found                          875 B          81.5 kB
├ ○ /pages/about                         2.16 kB        90.2 kB
├ ○ /pages/contact                       2.6 kB         92.5 kB
├ ○ /pages/experience                    2.25 kB        90.3 kB
├ ○ /pages/home                          2.02 kB          92 kB
└ ○ /pages/projects                      2.16 kB        90.2 kB
+ First Load JS shared by all            80.6 kB
  ├ chunks/472-0de5c8744346f427.js       27.6 kB
  ├ chunks/fd9d1056-138526ba479eb04f.js  51.1 kB
  ├ chunks/main-app-4a98b3a5cbccbbdb.js  230 B
  └ chunks/webpack-ea848c4dc35e9b86.js   1.73 kB


○  (Static)  automatically rendered as static HTML (uses no initial props)

Full image: Build with Next.js

I read in Next.js pages end in 404 on production build that perhaps it has something to do with having sub-folders inside the pages folder, but I’m not sure how to fix that as I wasn’t able to get it to work without sub-foldering page.js files for each page.

EDIT: Here is my next.config.js file:

/** @type {import('next').NextConfig} */
const nextConfig = {
    basePath: '/pages',
    output: 'export',
}

module.exports = nextConfig