My 2 cents
I'm sure the link provided will have this information too. Make sure that the transfer rate in your scanners settings matches those of both ARC and your port settings under device manager. Try different ports as well. Hope this helped.
Mt. Olive (Morris County), NJ
Bearcat IV, AR1000, AR8200 MK1 EU (Non-Blocked), BCD396T & BCD396XT