It could be that there was an internet interruption while connecting to our server. To refresh the data, you can sign out and sign back in. You might also have downloaded the QuickBooks Online app instead of the QuickBooks Self-Employed app.
Here’s a link that you can refer to in downloading the QuickBooks Self-Employed app for IOS and Android.
If you still can't access your account through the app, you can log in using a web browser on your mobile.
Let me know how this worked. I'd be around to help!