Angular language service in VSCode does not work because it is not an Angular project ('@angular/core/core.d.ts' could not be found)

Question

Somehow the Angular (v11.0.4) language service in VSCode does not work anymore. I get the following error message.:

[Info  - 17:52:04] Angular language server process ID: 147359
[Info  - 17:52:04] Using typescript/lib/tsserverlibrary v4.0.5 from ~/.vscode-oss/extensions/angular.ng-template-0.1100.2/node_modules/typescript/lib/tsserverlibrary.js
[Info  - 17:52:04] Using @angular/language-service v11.0.3 from ~/.vscode-oss/extensions/angular.ng-template-0.1100.2/server/node_modules/@angular/language-service/bundles/language-service.js
[Info  - 17:52:04] Log file: ~/.config/Code - OSS/logs/20210112T090839/exthost2/Angular.ng-template/nglangsvc.log
[Info  - 17:52:06] Disabling language service for ~/Workspace/NG_PROJECT/tsconfig.json because it is not an Angular project ('@angular/core/core.d.ts' could not be found). If you believe you are seeing this message in error, please reinstall the packages in your package.json.
[Error - 17:52:06] Failed to find project for ~/Workspace/NG_PROJECT/projects/apps/app1/src/app/*.html
[Error - 17:52:53] No config file for ~/Workspace/NG_PROJECT/projects/apps/app1/src/app/*.html
[Error - 17:52:54] No config file for ~/Workspace/NG_PROJECT/projects/apps/app1/src/app/*.html

I already tried:

rm -rf node_modules package-lock.json
npm cache clean --force
npm install

but it does not solve the problem.

What can I do to solve that issue?

Answer 1

Update to @Begandroide's answer. "Ivy" is no longer considered experimental, and so the Enable-experimental-ivy-prompt is no longer an option. With the latest major version (12.x...) of the Angular Language Service VSCode extension, you must enable the Use legacy View Engine language service option.

Answer 2

I'm facing the same issue and I resolved it by going to the marketplace of VS Code, then go to Angular language service extension and click on settings, then extension settings

Finally, you must disable experimental-ivy and reload window (VS Code)