Hi?@prexilated,
Thank you for reaching out.
We have seen possible issues installing keys automatically more than 24 hours after generation. Additionally, if you are in a different browser than the one used when requesting your Free Wordfence license, you will be unable to automatically install it. In those cases, you will need to manually copy and paste the key from the email to complete the activation of Wordfence Security.
Aside from verifying that you did not copy only part of the license key, I would check whether you can install the license when Wordfence is the only active plugin on your site. There could be a Javascript conflict with another plugin potentially stopping the code executing the verification check.
In some cases, disabling caching plugins resolves the issue.
Let me know how it goes.
Thanks,
Janet