There are no widespread issues reported regarding the loading screen for the QuickBooks mobile app on iPhone devices, Michael.
I suggest performing some mobile app troubleshooting, as the data stored on your device may affect its functionality and display. Follow these steps to reset it without deleting your app's documents and data:
Go to Settings, then tap General.
Select iPhone Storage, then click the QuickBooks Online app.
Tap Offload App.
If the issue persists, I recommend uninstalling and reinstalling the app to ensure that you have the latest version.
We can troubleshoot the issue using the steps provided above by my colleague, @PD Gas.
If you have completed all the steps and are still experiencing the same issue, I recommend reaching out to our Live Support team. This way, they can investigate further the cause and find the best resolution of this problem.
Here's how:
Go to Help (?).
Use QB Assistant to enter your query or question.
In Search, click Contact Us to connect with a live support agent.
Choose a way to connect with us:
Start a chat with a support expert. Live chat all day, M-F.
Call us. M-F, 8:00 AM to 10:00 PM, and S-S, 8:00 AM to 6:00 PM.
Lastly, here are articles to assist you in making sure you have the best experience when using QuickBooks Online (in web browsers or mobile devices) and learn the features available for iPhone.