Edit: The issue is solved, it is working now.
I purchased X theme yesterday, and trying to set it up to my website.
However, when I try to activate it, it redirects me to theme.co 's website to sign up with my envato username and licence key of my purchase.
After entering the details, I receive the following error message:
We’re having trouble connecting to the Envato’s server to validate your purchase code. Please try again in a few minutes.
Since there is no way to sign up to their website with another method, I cannot contact them to ask for support