1 files changed, 11 insertions, 1 deletions
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index b261e078c4..19293bf673 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -174,6 +174,16 @@ async def _handle_json_response(
         d = timeout_deferred(d, timeout=timeout_sec, reactor=reactor)
 
         body = await make_deferred_yieldable(d)
+    except ValueError as e:
+        # The JSON content was invalid.
+        logger.warning(
+            "{%s} [%s] Failed to parse JSON response - %s %s",
+            request.txn_id,
+            request.destination,
+            request.method,
+            request.uri.decode("ascii"),
+        )
+        raise RequestSendFailed(e, can_retry=False) from e
     except defer.TimeoutError as e:
         logger.warning(
             "{%s} [%s] Timed out reading response - %s %s",
@@ -986,7 +996,7 @@ class MatrixFederationHttpClient:
             logger.warning(
                 "{%s} [%s] %s", request.txn_id, request.destination, msg,
             )
-            SynapseError(502, msg, Codes.TOO_LARGE)
+            raise SynapseError(502, msg, Codes.TOO_LARGE)
         except Exception as e:
             logger.warning(
                 "{%s} [%s] Error reading response: %s",