autocomplete plugin is not working in ckeditor4-angular

In my project, I need to implement the CKeditor4 autocomplete with reference to https://ckeditor.com/docs/ckeditor4/latest/examples/autocomplete.html. I had followed the same approach in my angular project but it not working for me. My worked example is https://stackblitz.com/edit/ckeditor-autocomplete?file=src/app/app.component.ts