Flexible riser cards and GPUs

[DooDeLzZz]

I have a RX 480 Nitro+ OC graphics card and my custom build requires it to be further away from the Z270MX Gaming 5 mobo (flat open case build).
I’ve bought a PCIe x16 powered flexible riser card (Soarland SLPS070) to connect between them.

Now I’ve made the mistake of miscalculating the distance and the cable only reaches the x4 slot on my mobo. When connected to x4, it is powered and fans are spinning but the graphics card indicator led on my mobo turns on and no image is shown.

Does this happen because it is connected to the x4 slot or is it a problem with the riser card?
The riser card has a 4p Molex that is connected to my PSU.

 

[photonboy]

Connect the card directly to the x4 slot on the motherboard so you can see if that works or not.

If it works then the problem is the extender.