diff --git a/src/cdk/overlay/position/flexible-connected-position-strategy.ts b/src/cdk/overlay/position/flexible-connected-position-strategy.ts
index e70ac701d2de..9552c9c7ee7d 100644
--- a/src/cdk/overlay/position/flexible-connected-position-strategy.ts
+++ b/src/cdk/overlay/position/flexible-connected-position-strategy.ts
@@ -542,7 +542,7 @@ export class FlexibleConnectedPositionStrategy implements PositionStrategy {
     } else if (origin instanceof Element) {
       return origin;
     }
-    return document.body.lastChild as Element;
+    return null;
   }
 
   /**