ERROR Error: formControlName must be used with a parent formGroup directive. You'll want to add a formGroup directive and pass it an existing FormGroup instance (you can create one in your class). code example
Example: formControlName must be used with a parent formGroup directive.
<form [formGroup]="guestForm" novalidate>
<div class="panel-body">
<form> -> Remove this
<div class="col-md-12 col-sm-12">
<div class="form-group col-md-3 col-sm-6">
<label>First Name* </label>
<input formControlName="firstname" type="text" class="form-control input-sm">
</div>
</div>
</form> -> Remove this
</div>
</form>