Latitude 7410 and WD19DC and 2xQHD at 60Hz

I connected 2 dell external monitors U2722D (QHD) through the WD19DC to dell latitude 7410.
And now:
If I connect to 2xdisplayports, one of monitors is running at QHD 60Hz and the second at 2048x1040 at 29Hz.
How can I get QHD at 60HZ on the second external monitor.

I read in other posts that the 7410 supports DP HBR2, so I am surprised 2*QHD at 60Hz on DP does not work.

Have not tried yet to connect one monitor on DP and one on HDMI...