Hello, when I try to sign in to the app on my iPad it just says ‘oops, an error occurred‘ I can sign in online and on the app in my phone. How to fix this?

Hi bloodmoneymedia

Please check you have the most recent version of the app installed from within the app store, and that you're using the correct version for your subscription ('QuickBooks Self-Employed', or 'QuickBooks Accounting' for QuickBooks Online including Simple Start, Essentials, and Plus). 

Thanks!