in methods object, in the remote: function, in the success callback I had to add " delete validator.invalid[element.name];" in if (response) block, shown below

if ( response ) {

var submitted = validator.formSubmitted;

validator.prepareElement(element);

validator.formSubmitted = submitted;

validator.successList.push(element);

delete validator.invalid[element.name];

validator.showErrors();

}