1 files changed, 3 insertions, 3 deletions
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 6febc8618c..2f2bf3a134 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -227,7 +227,7 @@ class FederationClient(FederationBase):
                         for p in transaction_data["pdus"]
                     ]
 
-                    if pdu_list:
+                    if pdu_list and pdu_list[0]:
                         pdu = pdu_list[0]
 
                         # Check signatures are correct.
@@ -260,7 +260,7 @@ class FederationClient(FederationBase):
                 )
                 continue
 
-        if self._get_pdu_cache is not None:
+        if self._get_pdu_cache is not None and pdu:
             self._get_pdu_cache[event_id] = pdu
 
         defer.returnValue(pdu)
@@ -570,7 +570,7 @@ class FederationClient(FederationBase):
 
             res = yield defer.DeferredList(deferreds, consumeErrors=True)
             for (result, val), (e_id, _) in zip(res, ordered_missing):
-                if result:
+                if result and val:
                     signed_events.append(val)
                 else:
                     failed_to_fetch.add(e_id)