From the Onboard Admin (OA) main screen select the switch and check the Port Mapping... is there a link? (green)
Check also the port mapping of the server.... link?
What do you mean with "can't reach" ? What switch do you use? Is it manageable or not? If yes, does it have a correct IP address?
If there is no physical link, you may have a problem with your C7000 backplane. Check the connector on the server and also on the switch. Be careful not to slide a server or switch into another slot when the connector is damaged or you will damage another slot.
Do you use the server onboard network interface or a mezzanine card? Is the mezzanine in the correct place/slot in the server? I experienced customers that mixed up FC and ETH cards..... that will not connect.
Is it a physical problem or software?