New installation using the same license key is prohibited

I received a license key from Proofpoint for LogViewPlus, which I have been using for over a 3 years. Recently, I switched to a new laptop, so I uninstalled LogViewPlus from my old laptop and installed it on the new one. However, when I tried registering with my license key from Proofpoint, I encountered an error saying, 'New installs prohibited,' even though the license key is valid.

Could you please assist me in setting up my licensed version of LogViewPlus on my new laptop?

Thanks