Layer Slider Product activation

I have been trying to activate with the given key but the same error keep coming, I bought this theme for this functionality only and that is not working. thats sad.

Please solve the issue

Your license key appears to be invalid. Please take special care to enter it correctly without accidentally including spaces or other additional characters. Please note, you can’t activate LayerSlider with your theme’s purchase code. This can also be a temporary issue in our services. In that case please try it again in a few hours.

Bundled plugins can’t be ‘activated’ but will still work as required just without premium features like auto updates