diff --git a/.github/workflows/build_app.yml b/.github/workflows/build_app.yml
index 4db036757..b03d970b5 100644
--- a/.github/workflows/build_app.yml
+++ b/.github/workflows/build_app.yml
@@ -6,7 +6,7 @@ on:
       subdomain:
         description: "Which subdomain you want to build the android app"
         required: true
-        default: "master"
+        default: "sandbox"
 
 
 jobs: