Kindle app on ipad

Ensure that both your iPad and the Kindle App have been updated to their most recent software versions. The current version of iPadOS is iPadOS15.6.

Having updated your Kindle App, if the problem persists, see:

If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support

I use that app frequently and ran into this problem once.

• The first thing to consider isn’t that perhaps you have too many books loaded on your iPad. To check, open your browser and log in to Amazon. Select Accounts & Lists then Content and Devices. From there, you can remove samples and books from your iPad that you no longer need. The trick is to remove, NOT delete. This way, you still have access to everything.
• Next, I recommend deleting the app, then reinstalling it and signing in. This will reset the library on your iPad and also re-index everything.

This worked for me. I hope it helps you. Please let us know.