The most common reason why you can't send or receive WhatsApp messages is a bad Internet connection. Learn how to troubleshoot connection issues on: Android | iPhone | Windows Phone

If you're sure your phone is connected to the Internet, there are a few reasons why WhatsApp messages aren't going through:

• Your phone needs to be restarted or turned off and on.
• The contact you're messaging has blocked your number. Find out more in this article.
• You haven't completed the initial verification process. Learn about verification on: Android | iPhone | Windows Phone.
• The number of the contact you're trying to message on WhatsApp hasn't been saved correctly on your phone. Learn the correct format of each phone number here.