Behavior in QuickBooks Online (QBO) such as getting a blank white screen is often caused by too many cache files stored on your browser. That said, we'll want to perform a few troubleshooting to better isolate this issue.
Let's start by accessing your account through a private browser or incognito window. This is a good spot to start the troubleshooting since this type of browser doesn't store cache.
Here are some keyboard shortcuts that you can refer:
If it works, go back to your original browser and clear the cache. this eliminates irregular data and refreshes the program. Otherwise, you can try other supported browsers to help narrow down the cause of this behavior. You can also uninstall and reinstall the mobile app.
You can also have this Community page to guide you with future tasks and tips when using QBO, you might want to visit our Help Articles.
I'm always open if you have additional questions. I'll be around to help. Wishing you a great day ahead!