Greetings.
I would start by getting your c240 upgraded to a more recent set of firmware, which will also include firmware for your Intel X520 card.
Please confirm you have Intel optics for your transceivers, as the Intel cards are very fickle about only liking Intel transceivers.
From:https://www.cisco.com/c/dam/en/us/products/collateral/servers-unified-computing/ucs-c-series-rack-servers/c240m3-sff-specsheet.pdf
Use Intel SFP CDE2-SFP-1WLR or CDE2-SFP-1WSR
Many cards/NICs/CNAs, if they don't like the transceivers, then you will not see any ports initiated from OS/driver.
If there happens to be an Intel 'chipset' driver for your specific OS on the Cisco Drivers ISO, make sure that is installed.
Thanks,
Kirk...