If you're getting this error the first time setting up your purchase, you probably experienced your DAW freeze too. This is a problem we're working on fixing with PACE (the makers of iLok).
Sometimes if this happens, your license did end up getting deposited into your account, so you should check your account in the iLok License Manager to see if that's what happened.
Other times, your license does get stuck in the unattainable ether, and you'll need one of our support agents to heroically retrieve it. Please submit a support ticket here and provide your activation code so we can help you with this.
To take advantage of a second activation, you'll need to be using an iLok account with your license. If you're using the plugin but can't find it in your iLok account, see these instructions to get it registered to your account. If you're not sure, please submit a support ticket and provide your activation code so we can help.
Once you're sure that you have the license in your iLok account, you're ready to use your second activation. You can find detailed activation instructions here, but in short, when you get the activation window popup in your DAW after installing Soundtoys, you need to skip the page that asks you for your activation code by choosing "No". Next, if you're not already logged in then log into your iLok account and finish your activation by choosing your activation location.
You might be getting this message if your computer was repaired or had a hardware change. In this case, you'll need to submit a support ticket and provide your activation code so we can help.