It supposed to be ok with my server Dell poweredge 350 (to be honest, i didnt check this before i bought the server)
https://www.windowsservercatalog.com/item.aspx?idItem=CC26A1CC-BE77-41FC-8C71-B3906D82E6F8&bCatID=1282&qos=2000000001
Fortunaly for me, i got another server, same model, almost same applications installed, and it works like a charm. So i figured out it was not a matérial problem...
That's really strange, the problem showed up when i promoted the DC. Before this, it was ok.