resurrecting an old post, but i'm having the same issue with one of my S2500-24P-US, fitted with a FiberStore 10GBase-T SFP+ transceiver. successfully deleted stacking so all 4 SFP+ slots are access/ethernet ports and computer shows something connected but won't pull an IP from DHCP, and even if manually addressed - no connectivity. Any thoughts/help would be most appreciated!