You could try to see if the USB port is visible on a real computer instead of ASIAIR.
On MacOS, you can use System Information (can be reached through "About this Mac"). Select USB item under the Hardware category. All USB Ports and Hubs are shown there. Note existing ports before plugging the mount to the computer. Then see if a new port appears when you plug the mount in. If not, the mount is indeed not communicating, and ASIAIR will not see your mount's port either.
Some mounts have a switchable port (for example to switch between USB and WiFI, etc). Check your mount's manual to see what they say about PC connection.
Some mounts also require you to do star alignment before it switches on the serial port (a misaligned mount will cause a slew to crash an OTA on a German mount into the pier or tripod). I assume you have already done that, though, since there are explicit instructions for that in the ASIAIR Telescope Setup window. For a quick test (with no payload on the OTA in case of accidental movements) just confirm alignment of each star. You can do this in the day time and not waste clear nights.
If the port is available and you are conversant with computers, find the Communications Protocol documentation for your mount. I have written a MacOS program where you can type commands manually to a serial (USB or Bluetooth) port. That will show you if the mount is accepting actual commands.
https://www.w7ay.net/site/Applications/Serial%20Tools/
Be sure to select the same baud rate that is needed (while you are doing so, check to make sure the mount's baud rate agrees with ASIAIR's baud rate).
Type in some simple commands, like fetching the current RA or getting Version number, to see if the mount responds.
Chen
