To use the SMS/text messaging tools in VSys, you must have your own account with Twilio, the service provider used for sending and receiving messages. Communication with Twilio is done using their API, and accessing that API requires that VSys (and possibly the Standalone E-mail Robot) have access to their website, https://api.twilio.com.
Things our lawyers make us say
You are responsible for your own account, its security and any charges that you incur. Bespoke Software does not exercise any control over Twilio, its pricing, reliability or availability. If Twilio should no longer provide the services that VSys requires, you may find that SMS message sending and receiving are no longer available, and Bespoke Software cannot guarantee the immediate replacement of another provider.