This issue only needs to be tested in one device. In browser, login in our master site as admin. Go to "Site administration > Plugins > Manage authentication" and set the field 'Self registration' ( registerauth ) to "Disable" on 'Common settings' In the app, click to add a site and add our master site URL. In the credentials page, check that you can see the authentication instructions but not the button to create an account. Remember to re-enable the "Self registration" in the site to leave it as it was