How To Fix WhatsApp not Sending or Receiving Messages
Follow the instructions below
Verify Network Connection
Make sure that you’re using a reliable network connection. You can verify your connection by switching apps to see if you can connect to the internet.
If you have connection issues, then switch your connection from WiFi to cellular or vice versa. You can do this by tapping on the WiFi icon in your control centre.
Open up WhatsApp and make sure that you can send messages to other contacts, as the contact you’re trying to message might have blocked your number. In this case, you will not be able to send or receive messages from that contact. When this is done, I suggest you click here to verify server issues and maintenance for WhatsApp. You will be able to verify if there are any WhatsApp server issues in your location.
You can preview any reported problems, and utilize the Live outage map to see where problems are coming from. In case there is no surge in reports, and you’re still unable to send and receive messages then make sure that you have some available storage on your device.
On an iOS device, open up your native settings application. Navigate to General, iPhone Storage, and here you can see if you have any storage left. If not, then you can easily navigate through storage intensive apps and delete what you need the least. Lastly, I suggest you check if you can send messages with your account with another device. Your personal computer for example.