Can't start project on a different system: Module not found?!?

I copied my entire Vaadin application (as Eclipse & Maven project) over to a different system.

Compilation and application startup work OK, but as soon as I try to connect with the browser (which triggers the frontend compilation) I am stuck with:

Module not found: Error: Can't resolve 'cookieconsent/build/cookieconsent.min.js'

I re-ran a “npm install” in the root directory of the project but that didn’t help.

Since I don’t have much of a clue what’s going off here under the hood I have no idea what and how to fix this. What am I missing here? Any help appreciated!

Full log:

------------------ Starting Frontend compilation. ------------------
e[0me[34mie[39m e[90m?wds?e[39m: Project is running at http://localhost:56540/webpack-dev-server/
e[34mie[39m e[90m?wds?e[39m: webpack output is served from /VAADIN/
e[34mie[39m e[90m?wds?e[39m: Content not from webpack is served from U:\Documents\eclipse\workspace_Vaadin\TestApp\target\classes\META-INF\VAADIN, src/main/webapp
i ?atl?: Using typescript@4.0.3 from typescript
i ?atl?: Using tsconfig.json from U:/Documents/eclipse/workspace_Vaadin/TestApp/tsconfig.json
i ?atl?: Checking started in a separate process...
i ?atl?: Time: 1098ms
         Serving the 'stats.json' file dynamically.
e[31m×e[39m e[90m?wdm?e[39m: Hash: 37dc8e018fa33cfcef7c
Version: webpack 4.42.0
Time: 9690ms
Built at: 08/02/2021 18:45:15
                                                  Asset      Size        Chunks                                Chunk Names
           build/vaadin-0-d307f72adae69693680b.cache.js  16.7 MiB             0  [emitted]
 [immutable]
  [big]
  
           build/vaadin-1-f980c2feeb9a1aff3fe8.cache.js   397 KiB             1  [emitted]
 [immutable]
         
           build/vaadin-2-25cd85c3b420560f3de5.cache.js  21.7 KiB             2  [emitted]
 [immutable]
         
           build/vaadin-3-9c3f862cc97ee9287c3c.cache.js   344 KiB             3  [emitted]
 [immutable]
         
      build/vaadin-bundle-8340032f378b59477ffc.cache.js   286 KiB        bundle  [emitted]
 [immutable]
         bundle
build/vaadin-devmodeGizmo-ab0c65ccc111fa465397.cache.js   451 KiB  devmodeGizmo  [emitted]
 [immutable]
         devmodeGizmo
                                             index.html  1.08 KiB                [emitted]
                     
Entrypoint bundle = build/vaadin-bundle-8340032f378b59477ffc.cache.js
Entrypoint devmodeGizmo = build/vaadin-devmodeGizmo-ab0c65ccc111fa465397.cache.js
[../node_modules/.pnpm/registry.npmjs.org/@polymer/iron-icon/3.0.1/node_modules/@polymer/iron-icon/iron-icon.js]
 5.5 KiB {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@polymer/iron-list/3.1.0/node_modules/@polymer/iron-list/iron-list.js]
 59.3 KiB {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/router/1.7.2/node_modules/@vaadin/router/dist/vaadin-router.js]
 90.7 KiB {bundle} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-accordion/1.2.0/node_modules/@vaadin/vaadin-accordion/theme/lumo/vaadin-accordion.js]
 78 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-app-layout/2.2.0/node_modules/@vaadin/vaadin-app-layout/theme/lumo/vaadin-app-layout.js]
 81 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-app-layout/2.2.0/node_modules/@vaadin/vaadin-app-layout/theme/lumo/vaadin-drawer-toggle.js]
 87 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-avatar/1.0.2/node_modules/@vaadin/vaadin-avatar/theme/lumo/vaadin-avatar-group.js]
 234 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-avatar/1.0.2/node_modules/@vaadin/vaadin-avatar/theme/lumo/vaadin-avatar.js]
 73 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-board/2.2.0/node_modules/@vaadin/vaadin-board/vaadin-board-row.js]
 86 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-board/2.2.0/node_modules/@vaadin/vaadin-board/vaadin-board.js]
 78 bytes {0} [built]

[../node_modules/.pnpm/registry.npmjs.org/lit-element/2.3.1/node_modules/lit-element/lit-element.js]
 8.62 KiB {devmodeGizmo} {0} [built]

[../target/flow-frontend/Flow.ts]
 12.6 KiB {bundle} [built]

[../target/flow-frontend/VaadinDevmodeGizmo.js]
 36.8 KiB {devmodeGizmo} [built]

[../target/frontend/generated-flow-imports.js]
 6.94 KiB {1} [built]

[../target/index.ts]
 1.46 KiB {bundle} [built]

    + 568 hidden modules

ERROR in ../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-cookie-consent/1.2.0/node_modules/@vaadin/vaadin-cookie-consent/src/vaadin-cookie-consent.js
Module not found: Error: Can't resolve 'cookieconsent/build/cookieconsent.min.js' in 'U:\Documents\eclipse\workspace_Vaadin\TestApp\node_modules\.pnpm\registry.npmjs.org\@vaadin\vaadin-cookie-consent\1.2.0\node_modules\@vaadin\vaadin-cookie-consent\src'
 @ ../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-cookie-consent/1.2.0/node_modules/@vaadin/vaadin-cookie-consent/src/vaadin-cookie-consent.js 14:0-50
 @ ../node_modules/.pnpm/registry.npmjs.org/@vaadin/vaadin-cookie-consent/1.2.0/node_modules/@vaadin/vaadin-cookie-consent/theme/lumo/vaadin-cookie-consent.js
 @ ../target/frontend/generated-flow-imports.js
 @ ../target/index.ts
Child html-webpack-plugin for "index.html":
     1 asset
    Entrypoint undefined = index.html
    [../node_modules/.pnpm/registry.npmjs.org/html-webpack-plugin/3.2.0_webpack@4.42.0/node_modules/html-webpack-plugin/lib/loader.js!../target/index.html]
 1.13 KiB {0} [built]

    [../node_modules/.pnpm/registry.npmjs.org/lodash/4.17.20/node_modules/lodash/lodash.js]
 530 KiB {0} [built]

    [../node_modules/.pnpm/registry.npmjs.org/webpack/4.42.0_webpack@4.42.0/node_modules/webpack/buildin/global.js]
 472 bytes {0} [built]

    [../node_modules/.pnpm/registry.npmjs.org/webpack/4.42.0_webpack@4.42.0/node_modules/webpack/buildin/module.js]
 497 bytes {0} [built]

e[34mie[39m e[90m?wdm?e[39m: Failed to compile.
e[38;5;196m
------------------ Frontend compilation failed. ------------------

Fixed by deleting the entire node_modules folder and rebuilding.