diff --git a/frigate/util/config.py b/frigate/util/config.py
index 520a5f975..5486d3bcd 100644
--- a/frigate/util/config.py
+++ b/frigate/util/config.py
@@ -166,4 +166,4 @@ def get_relative_coordinates(
 
         return mask
 
-    return None
+    return mask