Problem of Dual use USB3.0 to HDMI

[Jimmy Foldager]

Hi

I am trying to use 2 x USB3.0 til HDMI in at setup for some of our customers.
the converter is build with chipset DL-3500 and do support MST for Windows and MAC

When i connect the first one it works fine.
But then I plug in the second. Then I can see both in the device manager.
But there is only picture on the first.
If I then Remove HDMI cable from the first one picture pop up on the second converter.

what ever i do i can only get one of them to show image. did try different computers and both windows 10 and 11

can someone explain why, or even better say how i get it to work

BR
Jimmy