If your Visitor isn't sending SMS messages there are a number of possible reasons.
Check if you have SMS tokens
- Your token is valid, and that isn't the issue - Your token is invalid. Contact email@example.com to buy an sms token
Check if you have access to the SMS service. Open http://sms.pronestor.com/smsgateway/smsgateway.asmx in a browser.
If it looks like this, you have access