Form Ajax

app/docroot/modules/custom/mymodule/src/Form/AjaxForm.php

@@ -127,7 +127,7 @@ class AjaxForm extends FormBase {
     return $response;
   }
 
-  public function validateEmailCallbackAjax(array &$form, FormStateInterface $form_state, $filed_name) {
+  public function validateEmailCallbackAjax(array &$form, FormStateInterface $form_state) {
     $field_name = 'email';
     $response = $this->getResponse($form, $form_state, $field_name);
     return $response;