Call to a member function get_error_message()

Trying to setup this plugin on my site but when we try to send sms it gives below error

Fatal error: Uncaught Error: Call to a member function get_error_message() on integer in /home4/cpduvwmg/wawre.greatitminds.xyz/wp-content/plugins/wp-sms/includes/gateways/class-wpsms-gateway-instantalerts.php:82 Stack trace: #0 /home4/cpduvwmg/wawre.greatitminds.xyz/wp-content/plugins/wp-sms/includes/admin/send/class-wpsms-send.php(114): WP_SMS\Gateway\instantalerts->SendSMS() #1 /home4/cpduvwmg/wawre.greatitminds.xyz/wp-content/plugins/wp-sms/includes/admin/class-wpsms-admin.php(119): WP_SMS\SMS_Send->render_page() #2 /home4/cpduvwmg/wawre.greatitminds.xyz/wp-includes/class-wp-hook.php(287): WP_SMS\Admin->send_sms_callback(”) #3 /home4/cpduvwmg/wawre.greatitminds.xyz/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(”, Array) #4 /home4/cpduvwmg/wawre.greatitminds.xyz/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #5 /home4/cpduvwmg/wawre.greatitminds.xyz/wp-admin/admin.php(254): do_action(‘toplevel_page_w…’) #6 {main} thrown in /home4/cpduvwmg/wawre.greatitminds.xyz/wp-content/plugins/wp-sms/includes/gateways/class-wpsms-gateway-instantalerts.php on line 82

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