When you activate a license, it generates a key file that is tied to the machine's hardware. After restoring to a new machine, your old license key file will not work with your new machine. 
You must re-license your plug-in as follows:
  • exit your DAW
  • open this folder:
    • macOS: ~/Music/Neunaber Audio/Wet Reverb/
    • Windows: ~/Documents/Neunaber Audio/Wet Reverb/
  • delete the file license.key
  • relaunch your DAW and re-enter your license key