@Solla-topee Many thanks for your reply. My model is the WPA4226 Kit(EU) and my MacOS version is 10.13.6. It is difficult now for me to reproduce this problem, as it had disappeared after a full...

I successfully installed my new AV600 Extender Kit and connected my Mac to the network. Everything works fine with one single strange exception: When watching videos (e.g. on YouTube, but also...