diff --git a/openlcb/datagramservice.py b/openlcb/datagramservice.py
index dd70f4f..8b0ae74 100644
--- a/openlcb/datagramservice.py
+++ b/openlcb/datagramservice.py
@@ -246,6 +246,9 @@ def handleDatagramReceivedOK(self, message: Message):
         # match to the memo and remove from queue
         memo = self.matchToWriteMemo(message)  # type: DatagramWriteMemo|None
 
+        # check for whether a match was found, indicating this was for us
+        if memo is None : return
+        
         # check of tracking logic
         if self.currentOutstandingMemo != memo:
             logger.error(