Yesterdag I could download WhatsApp on my new Fairphone. The problem was how to login to it!
My phone asks a unknown way to confirm my identity.
Today I can’t find the app back again. What should I do?
You can’t find it in the main screen (only guessing with the few information given), but can you find it in Settings > Applications > Whatsapp? If so uninstall it through here and reinstall it with App Lounge. And then share screenshots of the weird authentication message.
If it’s not visible in Settings > Applications then it’s not installed and you can install it again.