You will get this error:
An error occurred: This site could not communicate with the subscription server. Please try again in a few minutes. If the problem continues or you know this server does not have Internet access, then you will need to contact your provider in order to acquire and install a license manually.
...if you attempt to activate/update your software subscription service when allow_url_fopen is disabled in the php.ini file on your web host. You should enable allow_url_fopen in the php.ini file. If you do not have access to the php.ini file or do not know where it is, then you should contact your server administrator.