diff --git a/app/Http/Requests/RecurringInvoice/StoreRecurringInvoiceRequest.php b/app/Http/Requests/RecurringInvoice/StoreRecurringInvoiceRequest.php
index 4988103f7924..d478ebcd7959 100644
--- a/app/Http/Requests/RecurringInvoice/StoreRecurringInvoiceRequest.php
+++ b/app/Http/Requests/RecurringInvoice/StoreRecurringInvoiceRequest.php
@@ -49,7 +49,7 @@ class StoreRecurringInvoiceRequest extends Request
 
         $rules['invitations.*.client_contact_id'] = 'distinct';
 
-        $rules['frequency_id'] = 'required,integer';
+        $rules['frequency_id'] = 'required|integer';
 
         return $rules;
     }