Go to your polyfills.ts file and find the import statements commented out under the section /** IE9, IE10 and IE11 requires all of the following polyfills. */:
// import 'classlist.js'; // Run `npm install --save classlist.js`.
Uncomment the above import to have your app working with those IE browsers but don't forget to run the following command.
npm install --save classlist.js
You might be also required to uncomment the following import:
// import 'web-animations-js'; // Run `npm install --save web-animations-js`.
And not to forget to run the following command:
npm install --save web-animations-js
EDIT
In browserslist file, you may replace not IE 9-11 with IE 9-11.
Also, in tsconfig.json file, you may replace "target": "es2015" (or whatever) with "target": "es5".