Please try these steps in order. Once your issue is resolved, there's no need to continue to the next step.
Make sure you're using the latest version of the OverDrive app (available on these devices) by going to the App Store and checking for updates. After updating, check to see if your issue is resolved. If not, or if you were already using the latest version of the app, continue to step 2.
Close the OverDrive app and any other unneeded apps.
Double-tap the Home button to open your "recents" list.
Find the OverDrive app and swipe up to close it. Do the same for other unneeded apps.
Tap the Home button.
Open the OverDrive app and see if your issue is resolved. If not, continue to step 3.
Restart your device.
Hold down the Wake/Sleep button until the "slide to power off" slider appears.
Turn off your device.
Hold down the Wake/Sleep button to restart your device.
Open the OverDrive app and see if your issue is resolved. If not, continue to step 4.
Delete your app cookies.
Open the OverDrive app.
Tap the icon in the top-left corner of the app to open the Home menu.
Tap Settings.
Tap Delete app cookies.
Close the OverDrive app and re-open it to see if your issue is resolved. If not, continue to step 5.