Object Undefined when binding data from an Observable

This question might have been answered somewhere but solutions provided are not working for me or I’m not using them properly. I have a service that returns data from a call to .net core API. The data is returned but I cannot bind it to an object.

The data is returned by the following Company.Service.ts

export class CompanyListRequest{
    UserID: number
}

//Company.Service.ts

import { CompanyListRequest } from '@app/_models/Company/CompanyListRequest';
 import { CompanyListViewModel } from '@app/_models/Company/CompanyListViewModel';

@Injectable({
  providedIn: 'root'
})

export class CompanyService {
  private companyListRequest : CompanyListRequest;

  constructor(private http: HttpClient) { 
    this.companyListRequest = {
      UserID:2, //For simplicity
    }
  }

  getAllCompanyList(){
      return this.http.post<CompanyListViewModel[]>(`${environment.apiUrl}/Company/GetCompanyDetails`,this.companyListRequest);
  }
}

I’m trying to get data here for binding to front end.

//Company-list.Component.ts

import { CompanyListViewModel } from '@app/_models/Company/CompanyListViewModel';

export class CompanyListComponent implements OnInit {
  public data: Observable<CompanyListViewModel[]>;

constructor(
      private companyService: CompanyService,
      private alertService: AlertService
      ) {

      }

ngOnInit() {

      this.companyService.getAllCompanyList()
      .pipe(first())
      .subscribe(
        data => {
           this.data = data["ResponseObject"]; //this.data is Undefined
           console.log(data["ResponseObject"]);
        },
        error => {
          this.alertService.error(error);
        });
  }

}

console.log(data["ResponseObject"]) //Returns the following:
{Id: 1, CompanyName: "Kim Investments", LegalName: "Kim Investments", HoldingCompany: "Kim Investments", RegistrationNumber: "PJ/90390/998"}

this.data is Undefined. I have checked the CompanyListViewModel and properties are matching with what is returned.

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Source Url Object Undefined when binding data from an Observable