try to create a service code

serviceAddon.php

@@ -172,7 +172,7 @@ function serviceAddonGetEmailTemplatesArray() {
     return $emailTemplates;
 }
 
-function serviceAddonSendEmail($templateName,$serviceId, $serviceCode='') {
+function serviceAddonSendEmail($templateName,$serviceId, $serviceCode) {
     $result = localAPI('SendEmail', ['messagename' => $templateName, 'id' => $serviceId, 'customvars' => ['servicecode' => $serviceCode]]);
     if ($result['result'] == 'success') {
         return 'success';