No connection using connectx-6


I’m trying to connect our new servers to some switches, using connectx-6 cards. However, after connecting the cables, I still get “no network cable attached” indication and the link would not start. None of the indication lamps (switch-side, as I did not see any on the server adapter side) is lighting up.

I can however see, that the “light is on” on the lasers.

My setup is as follows:

We have two servers, containing each two network-cards of the type connectx-6 (MCX653106A-ECAT), which are connected over 8 cables in total to two third party switches. The issue is on all eight connections.

Firmware-version is everywhere 20.28.2006 (freshly flashed onto all devices)

Driver-version is 2.50.233170.0 (although I downloaded the latest WINOF2 - the driver 2.50.51000 is not being delivered with it)

Operating System: Windows Server 2019 Enterprise

GBIC: everywhere ACM761 (as it is connected to a third-party switch)

Cabling: MTP polarity B cables (nothing out of the ordinary)

Am I missing some crucial setup? Could it be driver related? Where could I download te latest 2.50.51000 driver?

Thanks for your assistance

Hello Serge,

Thank you for posting your inquiry on the NVIDIA Networking Community.

Based on the information provided, please make sure you are using a Validated and Supported cable/transceiver from the following list →

The GBIC you mentioned is not in the validated and supported list.

If after replacing the GBIC for a supported transceiver and you are still experiencing an issue, please do not hesitate to open a NVIDIA Networking Support ticket by sending an email to

Thank you and regards,

~NVIDIA Networking Technical Support