Form Validators error "Cannot create property 'validator' on string 'clientUserName''

I am trying to use Validators on my form inputs but get this error Cannot create property 'validator' on string 'clientUserName' I would like to resolve this error.

My html

<form [formGroup]= "userInfoForm" (ngSubmit)="onUserInfoFormSubmit()">
  <mat-form-field>                       
     <mat-label>User Name</mat-label>
     <input id="clientUserName" type="text" formControl="clientUserName" matInput>
  </mat-form-field>
</form>

My ts

export class ManageAccountClientComponent implements OnInit {
   userInfoForm: FormGroup;

   constructor(
    private formBuilder: FormBuilder
    ) { }

   ngOnInit(): void {

    this.userInfoForm = this.formBuilder.group({
      clientUserName: ['', Validators.required]
    });
   }
  
   onUserInfoFormSubmit(){
    window.alert('UserInfoFormSubmit');
  }

}