Looking for Answers about samsung S27A750D?

Occasionally, the monitor will turn black and display the following, "Not optimal display settings, please use 1920x1080". The video card is set to 1920x1080 @ 120Hz, so I'm not sure what the problem is. Cycling the monitor's input to HDMI, then back to DisplayPort gets it working again, but I would like to fix the underlying issue so I don't have to keep cycling the input.

I have three S27A750D monitors, and they each seem to have the same symptom occasionally. All three are connected to an ASUS EAH6950 with the Samsung DisplayPort cables included with the monitors. There are no adapters nor converters. Please help!

I'm using a DVI to DP setup amd just get check connection Plus I cannot get Monitor to go back to HDMI Tried every thing. Am using another moniter with DVI setup for now

I have tried turning on the monitor. Setting it to the various 3d modes (2d->3d, frame sequential, etc). Then pressing the power button on my 3d glasses that were supplied with the monitor. The power button on the glasses blinks green and red for a couple of minutes and then turns off. I would like to determine if it is the glasses or the monitor.

the first time i used the original displayport cable i had no trouble but after a while the screen went black so then i use the hdmi 1.4 and yes it workt in 120 hz for a while but then same story after a couple of days the flickering of the screen starts again so i ordered a very expensive displayport cable but the screen stays black like the origanel diplayport cable in the box pffffff omg this screen got some major issues i paid over 200 bucks on cables and still nothing has changed iif i knew this before i would never buy this screen look at the price its not normal you know look at what we pay for it and its not working....im thinking of selling