If your app is not accepting orders, the most likely cause is that the app is logged on at a time that is not within your typical operating hours with Uber Eats.
1. Double check you are within restaurant's operating hours.
2. If you are, press the small square button at the bottom of the screen.
3. Once all open apps have been minimized, swipe left to force close each app.
4. Once all apps have been closed, hold down the small external button on the side of the device.
5. Once the button has been held down, a screen will pop up prompting you to select either "POWER OFF" or "REBOOT." Select "POWER OFF" to shutdown the device.
6. Wait ~1 minute, and then hold down the button again to restart the device.