Dell Monitor P2417H and Display Port Issue

Hi All

We have a bit of an issue connecting a Dell P2417H monitor via Display Port. The laptop we are connecting to the monitor is a Del E6440 with Intel HD Graphics 4600. The laptop is connected to a Dell Dock and the monitor is connected to the dock, however we just get an error message saying 'No DP signal from your device. Press any key on the keyboard or mouse to wake it up'. The laptop is on and not in sleep mode.

I have made sure that the input source is on DP, I have completely removed the graphics card drivers and re-installed the latest ones from Dell, tried using a different DP cable and a different dock however no luck.

The monitor works fine if you connect it with VGA, it just wont work with DP.

One think I Can try is disabling DP 1.2 but there is no where on the monitor settings to do this?

Any help would be appreciated, I have tried searching on the net but can't seem to find anything related to this monitor.

Many thanks in advance.

Idrees