Dell P2415Q dosnt work on macbook pro 2016 (macOs 10.12.1) via displayport, only hdmi works.

Hello,

i bought a Dell P2415Q via check24 in germany.
This dell P2415Q Rv A01 doesnt work with my macbook pro 2016 (macOs 10.12.1) via displayport, only hdmi works. I tried displayport and mini-displayport.

Other people seems to have the same problem. What can i do?