diff --git a/application/controllers/admin/tokens.php b/application/controllers/admin/tokens.php
index 0a814d435e9..70bb10509d3 100644
--- a/application/controllers/admin/tokens.php
+++ b/application/controllers/admin/tokens.php
@@ -833,6 +833,10 @@ public function edit($iSurveyId, $iTokenId, $ajax = false)
                     $aTokenData[$attr_name] = $request->getPost($attr_name);
                 }
 
+                if (!empty($sOutput)) {
+                    \ls\ajax\AjaxHelper::outputError($sOutput);
+                }
+
                 $token = Token::model($iSurveyId)->findByPk($iTokenId);
                 foreach ($aTokenData as $k => $v) {
                     $token->$k = $v;
@@ -841,7 +845,7 @@ public function edit($iSurveyId, $iTokenId, $ajax = false)
                 $result = $token->save();
 
                 if ($result) {
-                    \ls\ajax\AjaxHelper::outputSuccess($sOutput . gT('The survey participant was successfully updated.'));
+                    \ls\ajax\AjaxHelper::outputSuccess(gT('The survey participant was successfully updated.'));
                 } else {
                     $errors = $token->getErrors();
                     $firstError = reset($errors);
diff --git a/application/views/admin/token/tokenform.php b/application/views/admin/token/tokenform.php
index 251ddf56858..72be7d23f94 100644
--- a/application/views/admin/token/tokenform.php
+++ b/application/views/admin/token/tokenform.php
@@ -24,9 +24,20 @@
 }
 ?>
 
+<div id="edittoken-error-container" class="row" style="display: none;">
+    <div class="alert alert-danger alert-dismissible" role="alert">
+        <button type="button" class="close" aria-label="Close" onclick="$('#edittoken-error-container').hide();"><span>×</span></button>
+        <span class="alert-content"></span>
+    </div>
+</div>
 <div class="row">
   <div class="col-md-12 content-right">
-    <?php echo CHtml::form(array("admin/tokens/sa/{$token_subaction}/surveyid/{$surveyid}/tokenid/{$tokenid}"), 'post', array('id'=>'edittoken', 'class'=>'', 'data-trigger-validation'=>true)); ?>
+    <?php echo CHtml::form(array("admin/tokens/sa/{$token_subaction}/surveyid/{$surveyid}/tokenid/{$tokenid}"), 'post', array(
+        'id' => 'edittoken',
+        'class' => '',
+        'data-trigger-validation' => true,
+        'data-validation-error' => gT("Some mandatory additional attributes were left blank. Please review them.")
+    )); ?>
       <!-- Tabs -->
       <?php if( count($attrfieldnames) > 0 ):?>
         <ul class="nav nav-tabs" id="edit-survey-text-element-language-selection">
@@ -417,7 +428,14 @@
                     <?php echo $attr_description['description'].($attr_description['mandatory'] == 'Y' ? '*' : '') ?>:
                 </label>
                 <div class="">
-                    <input class='form-control' type='text' size='55' id='<?php echo $attr_name; ?>' name='<?php echo $attr_name; ?>' value='<?php if (isset($$attr_name)){echo htmlspecialchars($$attr_name, ENT_QUOTES, 'utf-8');}?>' />
+                    <input
+                        class='form-control<?= $attr_description['mandatory'] == 'Y' ? ' mandatory-attribute' : '' ?>'
+                        type='text'
+                        size='55'
+                        id='<?php echo $attr_name; ?>'
+                        name='<?php echo $attr_name; ?>'
+                        value='<?php if (isset($$attr_name)){echo htmlspecialchars($$attr_name, ENT_QUOTES, 'utf-8');}?>'
+                    />
                 </div>
             </div>
             <?php endforeach; ?>
diff --git a/assets/scripts/admin/tokens.js b/assets/scripts/admin/tokens.js
index 8d5d162215b..9d6c601782f 100644
--- a/assets/scripts/admin/tokens.js
+++ b/assets/scripts/admin/tokens.js
@@ -149,8 +149,11 @@ function submitEditToken(){
         success : function(result, stat) {
             if (result.success) {
                 $modal.modal('hide');
-            }
-            else {
+            } else {
+                var errorMsg = result.error.message ? result.error.message : result.error;
+                if (!errorMsg) errorMsg = "Unexpected error";
+                showError(errorMsg);
+                return;
             }
 
             // Using Try/Catch here to catch errors if there is no grid
@@ -174,6 +177,33 @@ function submitEditToken(){
     });
 }
 
+function showError(msg) {
+    $('#edittoken-error-container .alert-content').html(msg);
+    $('#edittoken-error-container').show();
+}
+
+/**
+ * Validates that mandatory additional attributes are filled
+ */
+function validateAdditionalAttributes() {
+    const validationErrorMsg = $('#edittoken').attr('data-validation-error');
+
+    let valid = true;
+    $('.mandatory-attribute').each(function () {
+        let value = $(this).val();
+        if (value === null || value === "") {
+            valid = false;
+            if (!$('#custom').is(':visible')) {
+                $('.nav-tabs a[href="#custom"]').tab('show');
+            }
+            showError(validationErrorMsg);
+            $(this).trigger('invalid');
+            return false;
+        }
+    });
+    return valid;
+}
+
 /**
  * Scroll the pager and the footer when scrolling horizontally
  */
@@ -267,14 +297,21 @@ $(document).on('ready  pjax:scriptcomplete', function(){
         if($('#editTokenModal').length > 0 ){
             event.preventDefault();
             submitEditToken();
+            return;
+        }
+        if (!validateAdditionalAttributes()) {
+            event.preventDefault();
+            return false;
         }
     });
 
     /**
      * Save token
      */
-    $("#save-edittoken").click(function(){
-        submitEditToken();
+    $("#save-edittoken").off('click.token-save').on('click.token-save', function() {
+        if (validateAdditionalAttributes()) {
+            submitEditToken();
+        }
     });