Arduino can't connect to internet on 1 specific router (KPN Experia)

Hello all,

I have an Intel Edison Arduino and I want to connect to the internet. For testing, I have used the example code from the WiFiClient library to connect to the internet (https://www.arduino.cc/en/Reference/WiFiClient)

This works fine using the WiFi network at my work, and when I use my phone as hotspot. But when I use my router (KPN Experia box H368N), the connections fails. It does connect to the wifi (I get an IP) so DHCP is working, but when I try to connect to an external IP or website, the connection fails. Also when setting the DNS and Gateway manually, it fails.

Does anyone have any experience with this kind of behaviour? And a solution perhaps?

I have reset the router to factory default settings, but still no internet.