Dual monitor mac mini with 2 vertical monitors

I've used Sierra on my Mac Mini mid 2011. I tried to use 2 monitors vertical (hdmi+displayport dvi adapter) but the 2nd one doesn't do anything except seeing the mouse without anything else to change (desktop or windows). When I change the orientation one of the both monitors, both work as intended to but I cannot find how to make it work with both of them vertical. I changed the dock to appear to the other but still nothing. I updated to latest version of High Sierra and still the same problems.
Both monitors are DELL Ultrasharp 2410