error message with AsyncValidator is not visible - angularjs

Question

The required directive shows the red error message that works!
The uniqueschoolclassnumberValidator directive shows NOT the red error message!
From the server I always return exists => true, but I also tried it with false.
What do I wrong? The custom directive is triggered for sure!
Directive
'use strict';
angular.module('TGB').directive('uniqueschoolclassnumberValidator', function (schoolclassCodeService) {
return {
restrict: 'A',
require: 'ngModel',
link: function (scope, element, attrs, ngModel) {
ngModel.$asyncValidators.unique = function (schoolclass) {
var schoolclassNumber = "0a";
var schoolyearId = 1;
return schoolclassCodeService.exists(schoolyearId, schoolclassNumber);
};
}
};
});
Service
this.exists = function (schoolyearId, schoolclassNumber) {
var path = 'api/schoolyears/' + schoolyearId + '/schoolclasses/' + schoolclassNumber;
return $http.get(path).then(function (response) {
if (response.data == true) {
$q.reject("schoolclass number has already been taken");
}
else {
return $q.resolve();
}
});
};
Html
<form name="myForm">
<div class="col-sm-8">
<input type="text" unique-schoolclasnumber-Validator name="myInput"
ng-model-options="{ updateOn: 'default blur', debounce: {'default': 300, 'blur': 0} }"
ng-model="schoolclassNumber" class="form-control"
required placeholder="Enter schoolclass">
</div>
<div ng-messages="myForm.myInput.$error" style="color:red" role="alert">
<div ng-message="required">You did not enter anything.</div>
<div ng-message="unique">That schoolclass number already exists.</div>
</div>
</form>

Answer 1

In your service's exists method there should be return keyword before $q.reject:
if (response.data == true) {
return $q.reject("schoolclass number has already been taken");
}
else {
return $q.resolve();
}
Directive should be named uniqueSchoolclassnumberValidator instead of uniqueschoolclassnumberValidator (AngularJS change dash-delimited format to camelCase).
There is also a misspell in html code, in word "class". It should be unique-schoolclassnumber-Validator instead of unique-schoolclasnumber-Validator.