WhatsApp Web doesn't work on the phone When i try to start WhatsApp Web on the phone, the QR-Code scanner screen does not even open, but i get a passive notification "check your internet connection on the phone". 
While i can chat with WhatsApp without any problems, so the internet connection and the connection to WhatsApp cannot be the real problem.

How can i get Whatsapp to recognize that the internet connection is fine and open the qr code scanner?
It works after a Backup &amp; Reset:


Make a new local backup (via settings -> chats -> chat-backup)
uninstall WhatsApp
install WhatsApp
Login via Phone number and sms verification (even when there's a backup)
Whatsapp finds the local backup and asks if you want to import it. Nothing is lost, but a few settings. Profile image is restored, but for the screen name whatsapp asks you again (and suggests the name from your google account)


So if someone has the same problem: backup &amp; restore works fine.
Of course it doesn't hurt to have a TitaniumBackup, adb backup or similiar as well.