Airport Extreme losing 5GHz internet connection
When i connect any of my devices (iPad, iPhone or Mac) to the Airport Extreme i see the internet connection is dropping from time to time. I have started a continuous ping to an internal device and external website using the ip address and i see a timeout from time to time for the external website which can be more then 30 seconds. The internal devices stays reachable for ping on ip. This only happens on the 5GHz wifi and the 2.4GHz doesn't have this problem.
I'm confused because the problem is only with external destinations so after the modem and only for the 5GHz.
The software version is 7.7.3
The modem is a Docsis cable modem, Ubee EVW320
All help is welcome!
MacBook Pro with Retina display, OS X El Capitan (10.11.2)