Device connected but not showing in device manager

I have a Sharp XE-A201 cash register that has suddenly decided not to work on my PC.
The device does not show up in the device manager even when I set up the DM to show all hidden devices. The thing is, it works fine on my DH’s PC. This is the error message I get:

ECR-type error: Check machine type on ECR or COM on PC………….whatever tha means??
I checked the COM port using some type of software I downloaded & it is open. What am I not doing right?