경로가있는 컨트롤을 찾을 수 없음, FormArray Angular

코드 :

 ngOnInit() {
        this.formGroup = this.formBuilder.group({
          formArray: this.formBuilder.array([
            this.formBuilder.group({
              name: ['', Validators.required],
            }),
            this.formBuilder.group({
              dob: ['', Validators.required],
            }),
            this.formBuilder.group({
              sex: ['', Validators.required],
            }),
            this.formBuilder.group({
              snils: ['', Validators.required],
            }),
          ])
        });
      }