Hi there! I see your Happy Color app is crashing on your Kindle with Android 5.1.1. Let's try to get that fixed for you.

Could you tell me a bit more about when the app crashes? For example, does it happen right when you open it, while coloring, or at some other moment?

In the meantime, here’s a step-by-step guide to try:

1. Force Close the App: Open your app switcher (usually a button or gesture), find Happy Color, and swipe it away to close it completely.

2. Clear the App Cache and Data:
- Go to your Kindle’s Settings > Apps > Happy Color.
- Tap on Storage, then Clear Cache and if needed, Clear Data. (Clearing data resets the app and may require you to log in again, so only do this if you’re okay with that.)

3. Restart Your Kindle: Power it off completely and then turn it back on. This can clear temporary glitches.

4. Update the App: Check the Amazon Appstore or Google Play Store for any available Happy Color updates compatible with your device and install them.

5. Check Available Storage: Sometimes low storage causes crashes. Go to Settings > Storage to confirm you have enough free space (at least a few hundred megabytes is good).

6. Uninstall and Reinstall: If the above steps don’t help, uninstall Happy Color and then reinstall it fresh.

Given your device's older Android version, sometimes app compatibility can cause problems, but taking these steps often resolves common crashes.

Please try these and let me know if the crashes continue or if you see any error messages. That way, I can assist you further!

Are you satisfied with the solution I provided?