1. Go into your angular.json file
2. In that file, follow the path projects -> architect -> build -> options
3. Change "buildOptimizer" to true and add "aot" to true as well

The above commands should work now.

ADDON: If you have that problem with ng serve or ng test, you could try replacing build in step 2 with serve or test respectively (Disclaimer: I have not tested that).

When I upgrade from angular 11 to angular 13 I see this error during command ng serve. To fix it I created a brand new angular project with the "@angular/cli" and imitate the angular.json of the new project.

inside angular.json projects>MY_PROJECT_NAME>architect>build>configurations added a development with json

"development": {
  "buildOptimizer": false,
  "optimization": false,
  "vendorChunk": true,
  "extractLicenses": false,
  "sourceMap": true,
  "namedChunks": true
}

under ...serve>configurations added

"development": {
  "browserTarget": "hasap:build:development"
}

under ...serve> added "defaultConfiguration": "development"

You can see the details of changes in angular.json from my commit https://github.com/canbax/hasap/commit/9c0fc95fc244d35b2d7ee70c7048f6b38bd213b5

I used the production configuration to serve my project

 ng serve -o --ssl true --configuration production

This will use the buildOptimizer and the aot issue.