diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index c6062075690e..22732e9ea8d1 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -248,7 +248,7 @@ def __init__(self, msg: str):
         )
 
 
-class FederationDeniedError(SynapseError):
+class FederationDeniedError(RuntimeError):
     """An error raised when the server tries to federate with a server which
     is not on its federation whitelist.