The license file (zwoair_license), if it exist, should be in the BOOT volume of the microSD card, which is readable on plain macOS. If it does not exist and your ASIAIR can boot anyway, follow the instructions here on how to get a virtual license for the ASIAIR.
You enter the serial number as instructed, then slide that arrow button under the jigsaw puzzle until the last piece of the puzzle moves horizontally, and drops in place. You should then get a QR code, and ASIAIR will apparently scan it in and create a license. I have not tried this because I have saved the license files for all (4) of my ASIAIR units.
Complete instructions are here:
If the device does not beep after the ASIAIR "Pro" is powered on (v1 ASIAIR does not have a speaker) then you have failed to boot. See if you can find the original backup which you had made when you first received the ASIAIR. Restore from that microSD, and not one that you have already used and could possibly have corrupted (just like any computer, never, ever turn off power before soft powering the ASIAIR off).
If you really did not do a backup, go download the ZIP file from the Google drive that is linked by the URL above, and use ApplePi Baker to expand and burn it into a microSD card.
There are two links in that web page, one for ASIAIR and one for ASIAIR "Pro". Be sure you choose the correct one. They are not compatible.
The ZIP for the "Pro" is 6.3 GB, so it could take a while, depending on your ISP.
If you do not have sufficient download bandwidth from your ISP, your dealer should be able to help get you the ZIP file, and if you are in friendly terms with them, they may already have a stack of microSD cards that they have already programmed, and can just slip one in the mail for you. You will still need to follow the licensing procedure above.
Remember to back the microSD card up before you are even tempted to plug it into the ASIAIR. Make a copy of it using ApplePi Baler and use that secondary copy.