If you are trying to delete an order in the app and it is not working, most likely, this is because Fleet Mode is enabled. Fleet mode disables specific actions for drivers in the mobile app. One of those features is deleting an order.
If you need to delete an order from the app, you can contact your dispatcher and have them turn Fleet Mode OFF. You can find Fleet Mode in the Carrier TMS Settings under Settings > Driver App > Fleet Mode
You can learn more about Fleet Mode HERE