I have a Mac Mini from Late 2014 (2,6 GHz Dual-Core Intel Core i5, 8 GB 1600 MHz DDR3). I want to use two monitors with it - the two Monitors are identical BenQ GW2283. I managed to get both monitors running yesterday evening, but when I woke the system from sleep this morning, the problem was back again.
One Monitor is connected directly via HDMI. The other one is connected via Mini DisplayPort to HDMI. The monitors came with VGA connectors so I bought the HDMI cables and the Mini DisplayPort. As soon as two monitors are connected, the one that was first connected starts flashing, fading to black and shortly showing the system, then fading out again. I made a little video of this happening. The system does detect the second monitor, because I can move my cursor offscreen. The other monitor then prompts "no cable connected". This Problem seems to be related to order. Whatever monitor currently works will start flashing once I plugin the second one. It doesn't seem to matter whether I plugin the DisplayPort or the HDMI first.
I have tried resetting the NVRAM but that didn't have any effect. I hope to get some ideas or maybe even the answer to my problem from someone here, before I rush out and throw money at the problem by buying all sorts of other adapters.