Hi Bidisha, If you want to use the CloudAppServices of Mendix, you can add users via the launchpad. Go to home.mendix.com, press the i next to your app and click on Manage App Users. If you want to have local users, you can add users by logging in using as administrator. If MxAdmin is not configured (I think it's not default anymore for Sandbox), you can create an after Startup microflow which creates or updates an user.