Hi there, @wayne-legacysite .
Allow me to share some troubleshooting steps you can do to fix this.
First, I'd like to know if you're using the QuickBooks Desktop App powered by Windows? If yes, you may need to reset the app by clicking on the Help menu then selecting Reset App Data. If not, you can always drop a comment to let me know so that I can assist you more with this.
Then, check if you're still not able to see the mileage you've tracked on your phone. If you're still not able to see that, you can confirm it by logging in to QuickBooks Online through your preferred browser.
If you're able to see the transaction, you'll want to uninstall and reinstall the app. This depends on your operating system, you can follow the steps under the How do I uninstall the app? section in this article: QuickBooks App for Windows and Mac: General support.
I've added this article that can help you how to manage your mileage in the future: Automatically track mileage in QuickBooks Online. This also contains a sub-article on how to fix tracking issues in the mobile app.
I'm here to help if you need further assistance. Feel free to tag my name in the comment section below.
