diff --git a/delete-user-data/extension.yaml b/delete-user-data/extension.yaml
index 6f3c84decd..c919751fae 100644
--- a/delete-user-data/extension.yaml
+++ b/delete-user-data/extension.yaml
@@ -119,8 +119,8 @@ params:
       From which Realtime Database instance do you want to delete data keyed on a user ID?
     type: string
     example: my-instance
-    validationRegex: ^([0-9a-z_.-]*)$
-    validationErrorMessage: Invalid database instance
+    validationRegex: ^[^\.\$\#\]\[\/\x00-\x1F\x7F]+$
+    validationErrorMessage: Invalid database instance. Make sure that the instance name does not contain any of the following characters: . $ # [ ] /
     required: false
 
   - param: SELECTED_DATABASE_LOCATION