After registering the product key you'll need to run the XLN Online Installer to download, install and authorize your plug-in:
http://www.xlnaudio.com/install
The product key is invalid
Please check that the product key is entered correctly. If you type it out instead of using copy/paste, make sure to activate caps lock before you start typing.
The product key has already been registered to this account
You have already registered the license to the XLN Audio account with which you're logged in to the website. As soon as the product key has been used to register the product(s) you no longer need it, the license is now registered to your XLN Audio user account and available in the XLN Online Installer when logged in with that account. Open the XLN Online Installer and look in the top right corner and make sure you're logged in to the same account as the website, seen under Profile. If it's a different account in the XLN Online Installer then log out and log back in with the account seen under Profile at www.xlnaudio.com.
The product key has already been registered
The plug-in has been registered to a different XLN Audio account than the one you're logged in with on the website. Check the Profile page to see which account you're currently logged in with. The most common cause of this message is that you've created more than one XLN Audio account and the license has been registered to a different account email. If you know which XLN Audio account it was registered to then make sure you log in with that account on both the website and in the XLN Online Installer and you should be able to install and authorize your product(s).
If you can't remember which account you registered the licence to or you don't believe you've registered the license yet please contact XLN Audio Support, remember to share the product key in your message.
Splice Product keys
If you've registered the product key you received from Splice but the license is still not authorized open the XLN Online Installer and make sure everything is up to date. Look at the product name in the listing, if it has a Splice label then the product key has been registered to a different account than the one you're logged in with and the license is in that account. If you know which account you've registered it to then log out from the XLN Online Installer and log in with that account.
If you can't remember which account you registered the licence to or you don't believe you've registered the license yet please contact XLN Audio Support, remember to share the product key in your message.
If you realize that you've registered products to two different XLN accounts please get in touch with XLN Audio Support and we'll help you merge your accounts.