While in the dashboard click over the icon in the top-right corner and click on “Setting”.
Click on “Security Settings” and make sure that the “Disable send sms using API” is unchecked.
Click on “Manage Senders” and copy an existing sender name in the plugin’s field or create a new one by pressing on the “+” button in the top-right part of the page.
Click on “Developers” and then on “Applications”.
Copy the Bearer token (or create a new one) and put it in the related field of the plugin. Make sure that SMSs are enabled for the token.