Do you have a Kindle? Do you want it to work after today? Of course you do! If you have an older model of a Kindle eReader, there's an important update you need to perform NO LATER THAN TODAY!
Use this link to get the updates you need.
Here's the full warning, straight from Amazon itself:
Important: If you do not update your device by March 22, 2016, you will receive the following message on your device: Your Kindle is unable to connect at this time. Please make sure you are within wireless range and try again. If the problem persists, please restart your Kindle from the Menu in Settings and try again. If you see this message on your device on or after March 22, you will need to manually install the latest software update for your device. Go to Fire & Kindle Software Updates for more details.
So be sure to update your device before the day is done if you want to continue to download eBooks from the Cloud, Kindle Store and other Kindle services.