diff --git a/custom_components/bluesound_alt/media_player.py b/custom_components/bluesound_alt/media_player.py
index 9c57793..f491532 100644
--- a/custom_components/bluesound_alt/media_player.py
+++ b/custom_components/bluesound_alt/media_player.py
@@ -875,7 +875,7 @@ async def rebuild_bluesound_group(self):
 
         if self.is_master:
             # Add device itself to the start of array
-            new_device_group.append(str(self._id) + ":" + self.port)
+            new_device_group.append(str(self._id) + ":" + str(self.port))
 
             # Call to get slaves
             sync_status = await self.send_bluesound_command(