diff --git a/README.md b/README.md
index 276f644..25de778 100644
--- a/README.md
+++ b/README.md
@@ -322,6 +322,7 @@ Response code:
 - 403 Forbidden: Player id not valid, probably timeout
 - 409 Conflict: Invalid move, obstacle or position out of board
 - 422 Unprocessable Content: Validation error
+- 423 Locked: Game locked, product selection in progress
 
 Response body:
 ```json