diff --git a/mailjet.module b/mailjet.module
index faf3150..094ffd9 100644
--- a/mailjet.module
+++ b/mailjet.module
@@ -538,14 +538,18 @@ function mailjet_properties_sync($newField = null, $delete = false)
             $current_field = field_info_field($key);
 
             $field_type = 'str';
-            if ($current_field['columns']['value']['type'] == "int") {
+            if (isset($current_field['columns']['value'])) {
+              if ($current_field['columns']['value']['type'] == "int") {
                 $field_type = 'int';
+              }
+              if ($current_field['columns']['value']['type'] == "float") {
+                  $field_type = 'float';
+              }
             }
-            if ($current_field['columns']['value']['type'] == "float") {
-                $field_type = 'float';
+            elseif(isset($current_field['columns']['target_id'])) {
+              $field_type = $current_field['columns']['target_id']['type'];
             }
 
-
             $user_fields[] = array(
                 "Name" => str_replace('field_', '', $key),
                 "Datatype" => $field_type