diff --git a/chatmaild/src/chatmaild/dictproxy.py b/chatmaild/src/chatmaild/dictproxy.py
index f1299eb9..aa4ef9d1 100644
--- a/chatmaild/src/chatmaild/dictproxy.py
+++ b/chatmaild/src/chatmaild/dictproxy.py
@@ -20,6 +20,7 @@ class DictProxy:
 
     def handle_dovecot_request(self, msg):
         # see https://doc.dovecot.org/developer_manual/design/dict_protocol/#dovecot-dict-protocol
+        print(f"handling msg: {msg!r}")
         short_command = msg[0]
         parts = msg[1:].split("\t")
 
diff --git a/chatmaild/src/chatmaild/metadata.py b/chatmaild/src/chatmaild/metadata.py
index 5d886cb8..087a6765 100644
--- a/chatmaild/src/chatmaild/metadata.py
+++ b/chatmaild/src/chatmaild/metadata.py
@@ -74,7 +74,13 @@ class MetadataDictProxy(DictProxy):
             self.notifier.new_message_for_addr(addr, self.metadata)
         else:
             # Transaction failed.
-            self.transactions[transaction_id]["res"] = "F\n"
+            try:
+                self.transactions[transaction_id]["res"] = "F\n"
+            except KeyError:
+                logging.error(
+                    f"clearing transaction failed: {transaction_id} {self.transactions}"
+                )
+                raise
 
 
 def main():