Welcome back to the community, @miladbk! You could simply use this URL https://kc-eu.kobotoolbox.org/username instead of using this URL https://kc-eu.kobotoolbox.org/username/.
Kindly please note here that you have used / at the end which is not needed. Please also be informed that this URL only works if you are configuring the app where you are the admin owner of the project. If you are trying to collect data form someone else who shared the project with your account then this URL will not function as needed. In that case, you will need to follow this support article to configure your app’s server settings:
