问Flutter访问云开发数据库，返回DATABASE_PERMISSION_DENIED是怎么回事？

已匿名登录成功，访问云存储是正常的。

代码：

db.collection('tcb_hello_world').where({'name': ''}).get().then((value) => print("=== $value"));

打印的是：

=== {"code":"DATABASE_PERMISSION_DENIED","message":"[UnauthorizedOperation] No permission to operate. Please check your auth info, but if the problem persists, contact us.","data":null,"requestId":"477115adf5cda","total":null,"limit":null,"offset":null}