Cyclone V SoC, COM port issue

I had 2 cyclone V SoCs running perfectly on my laptop with access through the Tera Term. Later, I disconnected them and connected 2 other cyclone V SoCs. However, this time the Tera Term allowed only one access to the Serial Port. The other cyclone V SoC is represented as an external device that can be ejected in the Windows panel. The same behaviour exists with the old two SoCs now. The Device Manager in Windows also shows only 1 COM port, for the 2 SoCs connected.
Does anyone know what can be the issue here?