Please ensure that your devices are connected to the internet and restart your devices.
Check for updates for your device and the Kindle Reading App and update if needed.
Then try to sync your Kindle Reading App. Make sure that your mobile device is connected to the internet.
- Open the Kindle app.
- Select More from the navigation bar.
- Select Sync.
The last date synced updates to today’s date and time, confirming the sync is complete.