Use full path

web/inc/main.php

@@ -4,7 +4,7 @@ use PHPMailer\PHPMailer\PHPMailer;
 use PHPMailer\PHPMailer\SMTP;
 use PHPMailer\PHPMailer\Exception;
 
-if(!file_exists('vendor/autoload.php')){
+if(!file_exists(dirname(__FILE__).'/vendor/autoload.php')){
     trigger_error('Unable able to load required libaries. Please run v-add-sys-phpmailer in command line');
     echo 'Unable able to load required libaries. Please run v-add-sys-phpmailer in command line';
     exit(1);