ConnectX-4 not linking up

Hi! I purchased a NIC for my workstation, MCX415A-CCAT, latest firmware.

The link stays down. Mellanox sees the SFP and the cable and confirms the cable is running at 100G.

I’m connecting it via Cisco 40/100 BiDi SFP module to a Mikrotik 518. Port does not light up once connected to Mellanox. Other devices connect normally, so port, SFP and the fiber are OK.

I’ve disabled autoneg on both ends, forced 100G link, RS-fec Mellanox side, fec91 Mikrotik side, drivers installed, the card is visible in device manager.

The link stays down and Windows reports cable unplugged.

Mellanox throws error 36, which means negotiation/handshake is failing,

Windows 11 24H2.

Operational Info

State : Polling
Physical state : ETH_AN_FSM_ABILITY_DETECT
Speed : N/A
Width : N/A
FEC : N/A
Loopback Mode : No Loopback
Auto Negotiation : FORCE - 100G

Supported Info

Enabled Link Speed : 0x00f00000 (100G)
Supported Cable Speed : 0x00200000 (100G)

Troubleshooting Info

Status Opcode : 36
Group Opcode : PHY FW
Recommendation : Other issues

Tool Information

Firmware Version : 12.28.2302
MFT Version : mft 4.30.1-113

Any assistance would be appreciated.