Hi Robert,
Thanks for your purchase and sorry for the inconvenience regarding the license key activation.
I did a test with your license key and it is valid and does work, however it seems in your case, there is something getting in the way of the check.
Firstly do you have any security plugins installed such as Bullet Proof Security that may prevent AJAX from running on the backend? If not, we may need to look into your website so if you could provide temporary admin login details to: support@css-javascript-toolbox.com, we could take a look when we get a chance.
Kind Regards,
Damian Baker