the app logs out, not supposed to. Is there a fix?

The logout occurred due to a lack of activity, which is implemented to prevent unauthorized individuals from accessing your information, Kat. I can elaborate on the timeout feature and the sign-in duration for the desktop app.

QuickBooks Online desktop app will log you out after a certain period of inactivity for security purposes. This is why you're signed out after twenty (20) minutes of being idle, even though you have configured the timeout duration to three (3) hours. Please know that the system tracks your inactivity from the last movement of the mouse, click, or type on the keyboard.

Additionally, the app retains your login information and automatically launches QuickBooks Online once you sign in. If you do not sign out manually, you won't need to log in again for 6 months. However, refer to the steps below if you're experiencing unusual behavior to clear the accumulated cache:

1. Go to the Help icon at the top menu bar. 
2. Select Reset App Data.
3. Close and re-open your QuickBooks App for Windows/Mac.
4. Mark the Stay Signed In checkbox upon signing in to keep your credentials.

Moreover, the QuickBooks Online desktop app is only available to users in the United States, United Kingdom, Canada, and Australia. For additional troubleshooting tips, refer to this article from CA, which applies to other regions as well: Use the QuickBooks Online desktop app on your computer.

Lastly, explore this page to view the list of function keys and speed up navigation: QuickBooks Online Desktop App Windows Keyboard Shortcuts.

Staying logged in and using shortcuts is convenient so you can work efficiently. Return to this thread for further assistance in utilizing the desktop app. I'm always here to assist you in any way possible.