Before we start, could you please specify whether you've encountered any error message? This will help isolate the root cause of your concern.
In the meantime, let's perform some basic troubleshooting steps by ensuring your internet is stable and both your app and device are updated.
You can follow these steps to refresh your data:
For Android:
Go to Menu ☰, then tap More Options ⋮
Tap Settings, then Refresh Data.
Tap YES to confirm.
For iOS:
Go to Settings, then tap General.
Tap iPhone Storage, then tap the QuickBooks Online app.
Tap Offload App.
This will free up storage space while keeping your app's documents and data intact. If the issue persists, it's also bestto install and reinstall the application.