Thank you for your inquiry. We will be more than glad to assist you. Before we go any further. What are the SFP+ and SFP modules you are using? 3rd party modules may be causing this issue. Please take a look at this link as the Intel® Ethernet Converged Network Adapter X520-DA2 only works with Intel® modules.
Please let us know if this information helped you to find a solution.
they are intel FTLX8571D3BCV-IT
In this case, have you tried this card in a different system? What about the cables? Have you tried to update your BIOS firmware, According to your computer manufacturer website, this is the latest version FCKT58A. Check if you are running the latest firmware for your BIOS and if not, please update it from here.
Let us known please.