diff --git a/server.py b/server.py
index bc22ac5166976fdc81b877272ac3f68df411f687..c58db9f251e79efa0d9213e4b233cd25a8c80258 100755
--- a/server.py
+++ b/server.py
@@ -1824,7 +1824,7 @@ def make_calendar_from_protocols(protocols, summary):
         event["dtend"] = to_datetime(start + timedelta(hours=3))
         event["summary"] = protocol.protocoltype.short_name
         event["description"] = "\n".join(
-            top.name for top in protocol.get_tops())
+            top.name for top in protocol.get_tops() if top.name is not None
         calendar.add_component(event)
     content = calendar.to_ical().decode("utf-8")
     for key in config.CALENDAR_TIMEZONE_MAP: