The plugin license keys are all specific to the email address that was used to buy them in PayPal. For the Alamy plugin, the email address you gave as your Alamy login is used instead.

To enter the license correctly, you need to use exactly the same email address, including the same case, as your PayPal account. In Lightroom, open the Plugin Manager and highlight the appropriate plugin. You will then see text boxes for your email address and license key. Enter them exactly as in the email and click OK.

There are graphic instructions for doing this at here.

If a license is not being accepted then please make sure that you are running the latest version of the software by downloading it again from the website, either from the original product page or from the "Downloads" page.