How to track if SMS is not sent in MSG91 WHMCS SMS plugin?

Click on Send SMS tab in the Menu bar-

1. If the message is shown as sent then go to http://msg91.com and check the message in the Delivery Report.
2. If you are unable to find the message in Sent Messages logs, then, from your cpanel, open WHMCS database in PHP-myadmin and search for MSG91. 
3. Click on table name with setting suffix and check for the latest entry. You will see the APIs in the logs column.