Spawning from https://github.com/matrix-org/synapse/pull/13816#discussion_r993262622
@@ -248,7 +248,7 @@ class UserDeactivatedError(SynapseError):
)
-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.