If your Whatsapp is not working properly on your iPhone, then, the Whatsapp server, the old version, or the internet connection might be the cause. So, what you have to do is:

• Update your Whatsapp application, if you are using the old version

• Boost up the internet connection

• Clear the cache data

• And, one more thing is trying to reinstall the application

Read more: https://getassist.net/whatsapp-not-working-on-iphone/