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