diff --git a/tasks.py b/tasks.py
index 533124e..61df747 100644
--- a/tasks.py
+++ b/tasks.py
@@ -18,7 +18,7 @@ async def wait_for_paid_invoices():
 
 
 async def on_invoice_paid(payment: Payment) -> None:
-    if payment.extra.get("tag") != "lncalendar":
+    if not payment.extra or payment.extra.get("tag") != "lncalendar":
         # not a lncalendar invoice
         return