Thanks for posting in the Community. I'm here to lend a hand with the reconcile function not loading on the QBO App.
There are some recommended steps to take if the app isn't fully loading. The first step is to clear the cache of the app. Cache is stored in order to improve performance and loading, but too much can accumulate and interfere with processing. Here's how to clear cache in the app:
Click Reset App Data.
Also, uninstalling and reinstalling the QuickBooks Online app can help to resolve issues and ensure that the most recent version is installed. I recommend the following article as it contains additional insight on the app and troubleshooting: QuickBooks App for Windows and Mac: General Support.
Should you be unable to load the reconcile screen after following these steps, I recommend trying to load the page in a web browser. This can help to isolate and determine the cause of this behavior.
This should help to get you back to business and reconciling accounts.
As always, I'm only a post away if you should need further assistance. Best regards.