Connection problem with receiver

Hi all,
maybe you can help me with this problem that I am experiencing with one of my receivers.

The setup:
Receiver has been tested on WIFI and ethernet. This has no impact on how it is behaving.

The problem:
The receiver is not recognized by the router, neither on WIFI nor on eithernet.
After power up (and also after pushing the button for +5 seconds) it keeps blinking, mainly red but once in a while yelllow for a moment, then blue for a little while, then back to red.
Have tested all sorts of button pressing durations, power cable in and out...nothing.

Worth mentioning that 2 Booms, 1 Radio and 1 more receiver connected without ANY problems. So I cannot imagine an issue with my network configuration.

I also tried the udap console method but it would not find the player so no success there.

Any idea what else I could do?

Thanks for the help, as always.

Merc