Access to the port is denied with USB Bluetooth adapter

问题

I am connecting across a USB BlueTooth adapter.

All worked fine until today.

I execute this line...

 OurSpecificPorts.TheActivePortWeAreUsing.Open();    

I get this error

Access to the port 'COM34' is denied

What do I tell my user to do in this case ?

来源：https://stackoverflow.com/questions/14588457/access-to-the-port-is-denied-with-usb-bluetooth-adapter