Problems with your phone, computer, or Wi-Fi connection are some of the common reasons why you might not be able to send or receive messages on WhatsApp Web or Desktop.
If you’re unable to send or receive messages on WhatsApp from your phone, then you won’t be able to use WhatsApp Web or Desktop on your computer. Open WhatsApp on your phone and try to send a message. If you can't, learn more about how you can troubleshoot your phone connection: Android | iPhone
If you’re able to send a WhatsApp message from your phone, try using WhatsApp Web or Desktop on your computer again. If you still have issues sending or receiving messages, you may have a connection issue with your computer.
You must have a strong and stable Internet connection on your computer to use WhatsApp Web or Desktop. If you see a yellow banner above your chats list with the error message "Computer not connected", check to make sure your computer's Internet connection is active. If your computer's Internet connection is working normally and you still can't send or receive messages, refresh the page if you’re on WhatsApp Web or quit and restart the program if you’re using WhatsApp Desktop.
If the problem persists, try logging out and back in to WhatsApp Web or Desktop, which you can learn how to do in this article.
Note: For WhatsApp Web, you must use the latest version of Chrome, Firefox, Microsoft Edge, Opera, or Safari. Other browsers such as Internet Explorer aren’t supported.
If you’re using a managed Wi-Fi network, such as at an office, library or university campus, your network might be set up to block or limit connections to WhatsApp Web. If WhatsApp Web notifies you that you're on a Wi-Fi network that’s preventing WhatsApp Web from operating correctly, please make sure your network is set up to bypass traffic to "web.whatsapp.com", ".web.whatsapp.com", or ".whatsapp.net".