Invalid license error with NodeXL Pro

Oct 6 at 9:27 PM
I’m trying to install my existing license on a different desktop PC (in addition to my laptop). I believe you can install the license on multiple machines, just as long as they are not running NodeXL Pro at the same time. Well, I got a “license invalid” error when I tried to install it on the 2nd machine. I made sure the license file was downloaded from the original NodeXL email.

However, the one thing I forgot to do the first time I tried it was close the program on my laptop, so it was trying to run concurrently. But then, I closed the program on my laptop and I still get the same error when I point to the license file on the desktop. Am I supposed to clear out some program files before I try it again on the 2nd machine (the desktop)? What should I do?
Thanks,
Sal