Everything is safe with me, but I use the control via mainboard cable in combination with SignalRGB. Works flawlessly.

What exactly have you already tried? Try plugging the connection cables into a different port on the mainboard or even installing the cable in a different PC (if possible) and testing it. Otherwise, I would check the connections to the controller to see if they are correct (if you also have a GPU strimer cable, can you check if it works with the same controller?). If that doesn't help, the controller or the whole cable is probably defective.

Same thing with me, but with the Lian-Lee cable for the water cooling system! Nothing for 3 weeks and 4 emails to digitec. They told me to send the order number. 4 emails... Thought there was an echo but nothing.
Yes, some of the connections to the Connect adapters have loose contacts.
I knew I wasn't the only one 😂🙏😭