Sometimes some websites are not available. At last for instance kuketz-forum.de. Or some apps are not working, at the moment the ING banking app on iOS. This only happens on devices connected with my WLAN, but independently whether a device is using eBlocker or not. So, the only eBlocker provided function that these devices are using, is the DHCP server - becauce I use the manual settings for running a Fritzbox 7690 as internet access and WLAN router. When a device is not connected with my WLAN all websites and app services work properly.
What should I do in order to make all websites and services available for devices in my WLAN independently of using eBlocker or not?
Or - at least - what I have to do in order to find what causes this misbehaviour?