The computer is connected to the 10/100M adaptive switch for normal communication, but the 100M network interface card is connected to the switch with a red light, and the communication is abnormal.

This situation may be caused by improper configuration. The port of the switch is likely to be forced to 10M, and an error will only be reported when connected to 100M. The solution is to restore the port speed to adaptive or forced to 100M under the port configuration.