When you update your GB WhatsApp, FM WhatsApp, or Yo WhatsApp, whatsapp plus then this problem occurs.
There are 5 methods to fix this isssue.
1) Use official whatsapp - Uninstall moded apps and install whatsapp from play store.
3) Try to Sign in Whatsapp account using a different device - logout from primary device and try to use to login in another device.
4) Try to sign in using whatsApp web
5) Contact the WhatsApp help center
After trying all methods, if your problem is not solved that means your account is permanently blocked. You can only get your account back by showing the genuine reason to the help centre.