Thanks for contacting TextNow Support!
There's no harm in deleting the app and reinstalling it, as your messages and call history are backed up to our TextNow servers. (In fact, if you log into your account here at www.textnow.com, you should see them on your Text & Call Online page.)
On your iPad, try the following:
- Uninstall the TextNow app.
- Reboot your iPad.
- Reinstall TextNow from the App Store (not from a backup).
Hope that helps!