The list might be blank until you press the refresh button. Try that.
If you did already try that then you have to open the device manager on windows and see if the usb to serial adapter is listed. If it is not, and you are sure you have the driver installed, then I suggest you try another usb cable. Be sure the cable is not a charging only cable. Some do not have data capability. This has burned others on the forum.
If the cable is good, and the driver is good, and the iexos is powered and you are sure windows is working, then maybe the iexos has failed. But that is not likely.
How about when you give it all a go, if you have no luck you give us a step by step what you did relative to the configuration manager
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired