Here is what I did (with the advice from the programmers) to fix the problem.
1. Download the original license key file from the email, and put it in a non-shared folder. I found that OneDrive was especially problematic. Every time I opened the program, the license file was corrupted by OneDrive. Dropbox was a little better, but not a lot.
2. Go to the path where the NodeXL path file is stored. I searched for “NodeXL” on C: to find the folder. Then edit the file LicensePath and make sure the path to the license file you redownloaded in step 1 is correct.
3. Restart NodeXL. I had a ton of problems until I fixed the problem of storing the license in a synced folder. Once that was fixed, I was good.