diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 078ad0626d..22b9663831 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -114,7 +114,15 @@ class FederationServer(FederationBase):
         with PreserveLoggingContext():
             dl = []
             for pdu in pdu_list:
-                dl.append(self._handle_new_pdu(transaction.origin, pdu))
+                d = self._handle_new_pdu(transaction.origin, pdu)
+
+                def handle_failure(failure):
+                    failure.trap(FederationError)
+                    self.send_failure(failure.value, transaction.origin)
+
+                d.addErrback(handle_failure)
+
+                dl.append(d)
 
             if hasattr(transaction, "edus"):
                 for edu in [Edu(**x) for x in transaction.edus]:
@@ -124,6 +132,9 @@ class FederationServer(FederationBase):
                         edu.content
                     )
 
+            for failure in getattr(transaction, "pdu_failures", []):
+                logger.info("Got failure %r", failure)
+
             results = yield defer.DeferredList(dl, consumeErrors=True)
 
         ret = []
@@ -132,10 +143,16 @@ class FederationServer(FederationBase):
                 ret.append({})
             else:
                 logger.exception(r[1])
-                ret.append({"error": str(r[1])})
+                ret.append({"error": str(r[1].value)})
 
         logger.debug("Returning: %s", str(ret))
 
+        response = {
+            "pdus": dict(zip(
+                (p.event_id for p in pdu_list), ret
+            )),
+        }
+
         yield self.transaction_actions.set_response(
             transaction,
             200, response
diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py
index bb20f2ebab..6faaa066fb 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -91,7 +91,7 @@ class TransactionQueue(object):
                 if not deferred.called:
                     deferred.errback(failure)
                 else:
-                    logger.warn("Failed to send pdu", failure)
+                    logger.warn("Failed to send pdu", failure.value)
 
             with PreserveLoggingContext():
                 self._attempt_new_transaction(destination).addErrback(eb)
@@ -116,7 +116,7 @@ class TransactionQueue(object):
             if not deferred.called:
                 deferred.errback(failure)
             else:
-                logger.warn("Failed to send edu", failure)
+                logger.warn("Failed to send edu", failure.value)
 
         with PreserveLoggingContext():
             self._attempt_new_transaction(destination).addErrback(eb)
@@ -133,6 +133,15 @@ class TransactionQueue(object):
             (failure, deferred)
         )
 
+        def eb(failure):
+            if not deferred.called:
+                deferred.errback(failure)
+            else:
+                logger.warn("Failed to send failure", failure.value)
+
+        with PreserveLoggingContext():
+            self._attempt_new_transaction(destination).addErrback(eb)
+
         yield deferred
 
     @defer.inlineCallbacks
@@ -249,6 +258,15 @@ class TransactionQueue(object):
                     transaction, json_data_cb
                 )
                 code = 200
+
+                if response:
+                    for e_id, r in getattr(response, "pdus", {}).items():
+                        if "error" in r:
+                            logger.warn(
+                                "Transaction returned error for %s: %s",
+                                e_id, r,
+                            )
+
             except HttpResponseException as e:
                 code = e.code
                 response = e.response
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 1927948001..454c3d4ab1 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -146,14 +146,22 @@ class MatrixFederationHttpClient(object):
                     )
                     raise SynapseError(400, "Domain specified not found.")
 
+                if hasattr(e, "reasons"):
+                    reasons = ", ".join(
+                        f.value.message
+                        for f in e.reasons
+                    )
+                else:
+                    reasons = e.message
+
                 logger.warn(
-                    "Sending request failed to %s: %s %s : %s",
+                    "Sending request failed to %s: %s %s: %s - %s",
                     destination,
                     method,
                     url_bytes,
-                    e
+                    type(e). __name__,
+                    reasons,
                 )
-                _print_ex(e)
 
                 if retries_left:
                     yield sleep(2 ** (5 - retries_left))
@@ -447,14 +455,6 @@ def _readBodyToFile(response, stream, max_size):
     return d
 
 
-def _print_ex(e):
-    if hasattr(e, "reasons") and e.reasons:
-        for ex in e.reasons:
-            _print_ex(ex)
-    else:
-        logger.warn(e)
-
-
 class _JsonProducer(object):
     """ Used by the twisted http client to create the HTTP body from json
     """
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index e77eba90ad..79109d0b19 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -99,8 +99,6 @@ class Clock(object):
             except:
                 pass
 
-            return res
-
         given_deferred.addCallbacks(callback=sucess, errback=err)
 
         timer = self.call_later(time_out, timed_out_fn)