2 files changed, 9 insertions, 4 deletions
diff --git a/synapse/http/__init__.py b/synapse/http/__init__.py
index 0d47ccdb59..054372e179 100644
--- a/synapse/http/__init__.py
+++ b/synapse/http/__init__.py
@@ -25,7 +25,7 @@ class RequestTimedOutError(SynapseError):
         super(RequestTimedOutError, self).__init__(504, "Timed out")
 
 
-def cancelled_to_request_timed_out_error(value):
+def cancelled_to_request_timed_out_error(value, timeout):
     """Turns CancelledErrors into RequestTimedOutErrors.
 
     For use with async.add_timeout_to_deferred
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py
index db455e5909..87a482650d 100644
--- a/synapse/http/endpoint.py
+++ b/synapse/http/endpoint.py
@@ -115,10 +115,15 @@ class _WrappedConnection(object):
         if time.time() - self.last_request >= 2.5 * 60:
             self.abort()
             # Abort the underlying TLS connection. The abort() method calls
-            # loseConnection() on the underlying TLS connection which tries to
+            # loseConnection() on the TLS connection which tries to
             # shutdown the connection cleanly. We call abortConnection()
-            # since that will promptly close the underlying TCP connection.
-            self.transport.abortConnection()
+            # since that will promptly close the TLS connection.
+            #
+            # In Twisted >18.4; the TLS connection will be None if it has closed
+            # which will make abortConnection() throw. Check that the TLS connection
+            # is not None before trying to close it.
+            if self.transport.getHandle() is not None:
+                self.transport.abortConnection()
 
     def request(self, request):
         self.last_request = time.time()