1 files changed, 5 insertions, 0 deletions
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 09ed74f6ce..00b98af3d4 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -651,6 +651,11 @@ def respond_with_json_bytes(
     Returns:
         twisted.web.server.NOT_DONE_YET if the request is still active.
     """
+    if request._disconnected:
+        logger.warning(
+            "Not sending response to request %s, already disconnected.", request
+        )
+        return
 
     request.setResponseCode(code)
     request.setHeader(b"Content-Type", b"application/json")