Hello everyone!

Attempt no. 2.

I'm using Kali Linux 2.1.2 installed on my Raspberrry Pi 3. It serves as a access-point, and everything works. But for one thing.
I can only use Whatsapp - this is no joke. Only text messages will be transfered. No pictures and no voice messages.

Two guesses:
No. 1: My router uses IPv6 - could this be a problem? I don't really think so.
No. 2: I think that I've read somewhere that I have to increase the package-size with iptables. Is this true?

Thanks in advance!

Greetings