Error WP Online Contract

Hi, I just bought WP Online Contract and when I enter my purchase code I get an error 404. Any idea how to fix this?

Hi,

Please contact the author of your purchased plugin, the plugin author will assist you.

How to contact an author to get support or for any technical query:
https://help.market.envato.com/hc/en-us/articles/203039054-How-to-contact-an-author

Thanks