If you can not activate license with this message, something on your site/server is blocking the connection from your site to ours. It is usually due to a security setting on server, missing libraries or 3rd party plugin (in most cases security plugins).
Some security plugins can block outgoing/incoming requests. Disable all 3rd party plugins (except Envo Extra, Elementor/WooCommerce) and try it again please.
Your host may have an outgoing firewall on their server with a defined IP address, so adding our site to it will hopefully allow you to successfully activate your license key. Try asking your web host to add our site to their outbound firewall.