If this doesn't work contact support with the book title, ISBN, and error messages, and exactly what the problem is. There could be a brief delay, but the book should appear in your Kindle app under Docs - if you do not see the book within an hour try syncing your app and clicking the Send to Kindle button once more. If you see the Send to Kindle button, press it once. In your NetGalley account, go to the Start Reading section of your Shelf to see a list of all the books you’ve been approved to access and easily view the available download options for that book. After you leave it in this mode for a bit, turn airplane mode off and try syncing again. Find the book you want to read on your Kindle. Try putting your device in airplane or flight mode for about 30 seconds.

Click 'Add a new approved e-mail address,' enter and click Add Address. In your Amazon account, go to MANAGE YOUR CONTENT AND DEVICES page, then click on the Preferences tab, and scroll down to “Approved Personal Document Email List”.In the Devices section, click 'EDIT' under 'Send to Kindle,' enter your address in the Kindle Email field. Sign into, and click on Profile in the main menu bar at the top of the screen.You can also find this email address by going to Settings. If you update your Kindle app to version 2.9 or greater, you should be able to find your email address the next time you open the app. The Kindle app for devices has its own Kindle email address.Yes, you can use the Kindle app on most reading devices, and here's how:

Does kindle app sync between devices