Wanted to create a specific article for the issue I had with this app just in case someone else runs into the same issue. When I updated to the latest June security release on my Nexus 6P and tried to open the Flex Delivery app it threw an error saying my phone was rooted and the app would not run. My phone is not rooted at this time, never has been, and my boot loader is all locked up. So not sure why they thought my phone was rooted. I verified with Root Checker that it was indeed not rooted. Short answer, the fix was to uninstall the app and reinstall it, seems to be running fine now.