diff --git a/sanic/server.py b/sanic/server.py
index ee45e81b..f044517e 100644
--- a/sanic/server.py
+++ b/sanic/server.py
@@ -349,7 +349,7 @@ def serve(host, port, request_handler, error_handler, before_start=None,
 
     trigger_events(before_start, loop)
 
-    connections = connections or set()
+    connections = connections if connections is not None else set()
     signal = Signal()
     server = partial(
         protocol,