IPTV not working, when TV is connected via ethernet

[charltonathletic]

Very strange issue.
Neither Perfect Player nor XCIPTV works, if my Sony Android TV is connected via ethernet.
Absolutely no issues, if it's connected via WIFI.
But the ethernet connection is fine. Speedtest confirms this (we've got a 200/20 connection) and Netflix and Youtube works fine, just IPTV services.

 

[charltonathletic]

Just to add that Perfect Player and XCIPTV loads and shows EPG. But when I try to watch a channel, it buffers extremely heavily. We're talking about a frozen image for maybe 20 seconds, then it runs for about 1 second, before it freezes again.