This API was deprecated and is being kept only for existing users.
Go to your account homepage to copy the secret key requested by the plugin to use the Clockwork service…
and paste it into the plugin settings.
The service allows you to make use of a test credit. You must insert your phone number in the “Free Credit” section.
The service doesn’t require you to show a specific number as the sender of the message, therefore you can insert whatever value in the “Sender telephone number” field.