Hello,
First of all make sure about the version of plugin. you should using latest version. Then enable WP_DEBUGin your wordpress and try to open send sms page.
Regards
Fatal error: Uncaught exception ‘Services_Twilio_RestException’ with message ‘The requested resource /2010-04-01/Accounts/social@xyz.com.json was not found’ in /var/www/vhosts/xyz.com/httpdocs/wp-content/plugins/wp-sms-pro/includes/classes/webservice/includes/twilio/Twilio.php:305 Stack trace: #0 /var/www/vhosts/xyz.com/httpdocs/wp-content/plugins/wp-sms-pro/includes/classes/webservice/includes/twilio/Twilio.php(174): Services_Twilio->_processResponse(Array) #1 /var/www/vhosts/xyz.com/httpdocs/wp-content/plugins/wp-sms-pro/includes/classes/webservice/includes/twilio/Twilio.php(194): Services_Twilio->_makeIdempotentRequest(Array, ‘/2010-04-01/Acc…’, 1) #2 /var/www/vhosts/xyz.com/httpdocs/wp-content/plugins/wp-sms-pro/includes/classes/webservice/includes/twilio/Twilio/InstanceResource.php(79): Services_Twilio->retrieveData(‘/2010-04-01/Acc…’) #3 /var/www/vhosts/xyz.com/httpdocs/wp-content/plugins/wp-sms-pro/includes/classes/webservice/twilio.class.php(42): Serv in /var/www/vhosts/xyz.com/httpdocs/wp-content/plugins/wp-sms-pro/includes/classes/webservice/includes/twilio/Twilio.php on line 305
That is what I get. I have replaced the site address with xyz.com.
It’s seems you using the Pro pack (Old version)
Click here for get latest version of plugin.
Regards