Can't connecr second controller

[olmaf]

Hi,
I need a help. I tried to connect the second controller as explained in the instruction and seen in videos.
I get to the point when I click Camera button of the second tablets app. It shows disconnected and I don't see master and slave options, photo attached. Thanks in advance!

 

[olmaf]

The USB port was wrong, replaced by a new one in the shop, works fine.