There are components of IE (Internet Explorer) in that window. If you have restrictions on IE (some do), the 'Activate' but may fail to respond to clicks. The options are:
-Set IE to its default settings
-Use the command line to activate:
https://forums.stardock.com/486311/accounts-and-activation-support-faq#activatecommandprompt
Note: The latter will not work for the trial - only for the paid version of the product.