Solution:Troubleshoot the problem in the following way:
1.Confirm if the driver is installed correctly (whether the device manager has an exclamation mark or question mark);
2.Confirm that the rates on both ends of the NIC are the same (whether the NIC rate has been modified);
3.It is necessary to confirm the connection distance and network cable type between the two network cards (CAT6A is recommended for 10Gig rate, use CAT6 for less than 30 meters);
4.Try replacing a normal network cable (CAT6A).The customer feedback that he inserted the wrong slot. After replacing the slot, the X550-T1 network card can be used normally.