Experiencing contacts not showing up on WhatsApp can be a common issue on Android and iPhone.Possible reasons for contacts not appearing on WhatsApp include lack of contact permission, unsaved contacts, server issues, or outdated app.To troubleshoot, first ensure the contact is saved in your phonebook and then refresh WhatsApp contacts.Grant contact permission to WhatsApp, check for server status, and save contacts in international format if needed.Clearing WhatsApp cache, updating the app, and reinstalling it are additional steps to resolve the problem.If all else fails, reinstalling WhatsApp can be the final solution to missing contacts.Keeping apps updated and following these steps can help in fixing contacts not showing up on WhatsApp.