@Schimietzeu90 How is the box connected to router, directly with an Ethernetcable or a Switch or WLAN or Powerlan?
With Lan: First, please all the cables the box to the router. Then, please perform a new start, by disconnecting the power supply of boy for about 10 s - 30 s. If it doesn't help, please try to reset the box with paper clip in the small hole in the rear panel or the bottom of the box (depending on the type of box). if this doesn't help you can do the same with the router, and if this doesn't help, then I would call the hotline 0800 800800. No worries, if you reset the box, nothing on the box will be deleted.
If you use WLAN or Powerlan could you please connect the router directly with delivered Ethernetcable to the TV Box a take a look if it works now?