internet connection stops working when i connect vu+ duo 4k

What is the "deco" please ?

If the "deco" means a decoder (i.e. satellite receiver), the problem may to be anywhere. :)

Against the conflict of the same two IP addresses, each new router should be protected (it will not use a device that has been connected to the router as a second, with a fixed and identical IP address). I also think the problem will not be the same IP address.

Even though many set-top boxes still have a fixed IP address after rebooting, it has been detected even as DHCP from a previous state, but that is a rarity. Usually, every time the set-top box is booted, it asks for a new IP address from the router, which gives it a free IP address.

So there is probably no conflict of matching IPs.

I would also diagnose a mistake on another network - with another router or with a friend's router, etc. . Maybe your set-top box is streaming something to the internet and it is braking the whole network :). However, starting to solve the problem of setting up a computer network in a set-top box via the Enigma GUI MENU is also not a bad idea. Alternatively, check the cables, but they should probably have no effect on the problem.