Activation error - An error occurred while reading server response

With WooCommerce activation a message appears after inserting Activation Key.

An error occurred while reading server response.

activation error msg

What is the issue about?

I believe that’s a version of PHP thing. Simple workaround (though not necessarily the most secure approach) is to run a version of PHP 7.3 or less. Correct answer is I think the fatfree library that ships with the activation kit needs to be updated to be 7.4 compatible.