UP2516D, Apple, Calibration

Hello there,

I Recently bought the monitor UP2516D. I calibrated it with Xrite and I cannot make it works properly. The monitor is showing a much darker picture than my others Mac monitors. How can I fix it this issue? It's driving me crazy. Also it looks a bit more Greenwich than it was supposed to be. I'm not an expert in colors, just need to make this monitor to work properly for my job as a photographer. 

Help anyone, please!