Net TV Connection keeps "disconnecting" when watching NetTV provided Video

[GGKGGK]

Hi all .. I am new to this forum so I apologize up front if I posted this in the wrong section.

The setup:
TV = 37PFL8605K/02
Connection = WLan
Provider = TeleCom, setup with the ports open for TV (like on XBox)

The problem:
NetTV does connect - I get the apps and can surf and can use (most) other features. However, when calling up a video (Cinema preview, ARD/ZDF Mediathek or any other), in irregular intervalls (sometimes after a few seconds, sometimes after a few minutes, sometimes after a longer period of time) the window "disconnected" pops up, the video stops and everything returns to the NetTV main page.
I read about problems with the disconnection after a set amount of time (e.g. always after 30min.) but this is not my problem. It is irregular and as stated above, sometimes the video does not even start.

Has anyone got an idea what I might be doing wrong or where the problem lies?

[Toengel]

Hi,

this could be due to a bad WLAN reception (and consequently the connection speed)... You can try for testing purposes a LAN cable...

Toengel@Alex

[GGKGGK]

Hi Toengel - thanks for the answer.
Have not tried the cable yet (have not got a cable long enough). Checked the signal strength shown under settings on the TV and it shows a strong signal, speed 65 (mbit?).

Could it also be that the speed is too slow ?
Could it also be another setting I need to arrange on the router ?
Could it also be the WiFi Stick (the philips one I bought with the TV), although the streaming worked the first year.