Hi newbornnoise-gma,

Thank you for reaching out to us.

With QuickBooks Self-Employed, you can access your account either on a web browser or mobile app. 

If you're able to access your QuickBooks Self-Employed on a web browser without any error, you may try to clear your app's cache or uninstall/reinstall it. 

To install/download the app, go to your app store and search for QuickBooks Self-Employed. Once you've successfully installed the app, enter your login details and confirm. 

Let me know if you have any other questions by leaving a comment below. Have a nice day!