To use the LogonBox Cloud Messaging service for SMS you should navigate to the Authentication Flow Options page in Administration->Authentication Flows->Authentication Options->SMS.
The Provider option here should be set to LogonBox Cloud SMS if it is not already set to this by default.
The SMS Provider does require credits to be able to process and send the SMS messages, If you navigate to Dashboard->Server Status you can see a widget that details how many credits are currently available.
If you require additional credits then simply select the Buy More Credits option and you will be directed straight to the checkout where you will be able to purchase more credits for the system.
