AngularJS – ng-disabled not working for Anchor tag

There is no disabled attribute for hyperlinks.
You can do this:

.disabled {
  cursor: not-allowed;
}

<a ng-click="disabled()" ng-class="{disabled: addInviteesDisabled()}">Add</a>

$scope.disabled = function() {
  if($scope.addInviteesDisabled) { return false;}
}