Text are not working for NgbActiveModal For Angular

Question

I am using NgbActiveModal to openmodal however modal popup is getting open but I am unable to select nor enter something in text area of that popup modal

//html
<textarea rows="3" [(ngModel)]="testnotes" class="someClass" placeholder="Enter Some text here"></textarea>

//.ts
import { NgbActiveModal } from '@ng-bootstrap/ng-bootstrap';
testnotes: string = '';

//Style CSS
.someClass{
clear: both;
}