1 files changed, 3 insertions, 2 deletions
diff --git a/synapse/server.py b/synapse/server.py
index c4e025af22..f0a60d0056 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -221,8 +221,6 @@ class HomeServer(metaclass=abc.ABCMeta):
     # instantiated during setup() for future return by get_datastores()
     DATASTORE_CLASS = abc.abstractproperty()
 
-    tls_server_context_factory: Optional[IOpenSSLContextFactory]
-
     def __init__(
         self,
         hostname: str,
@@ -258,6 +256,9 @@ class HomeServer(metaclass=abc.ABCMeta):
         self._module_web_resources: Dict[str, Resource] = {}
         self._module_web_resources_consumed = False
 
+        # This attribute is set by the free function `refresh_certificate`.
+        self.tls_server_context_factory: Optional[IOpenSSLContextFactory] = None
+
     def register_module_web_resource(self, path: str, resource: Resource) -> None:
         """Allows a module to register a web resource to be served at the given path.