I am able to connect to outlook very easily but not able to connect with php only.

2. 
   
3. $mail=new PHPMailer();
6. $mail->isSMTP();
7. $mail->Host='smtp.zoho.com';
8. $mail->SMTPAuth=true;
9. $mail->Username='help@odekh.com';
10. $mail->Password='password';
11. $mail->SMTPSecure='tls';
12. $mail->SMTPDebug=3;
13. $mail->Port=587;
16. $mail->From='help@odekh.com';
17. $mail->FromName='Help Help';
18. $mail->addAddress('anyaddress@gmail.com');
20. $mail->Subject='Testing';
21. $mail->Body='Testing body';
23. if($mail->send()){
24. var_dump('mail is sent');
25. }

Please help me as the error is: 

2017-07-21 18:15:52 Connection: opening to smtp.zoho.com:587, timeout=300, options=array ( ) 2017-07-21 18:15:53 Connection failed. Error #2: stream_socket_client(): unable to connect to smtp.zoho.com:587 (Connection refused) [/home/rshbhchauhan/vendor/phpmailer/class.smtp.php line 294] 2017-07-21 18:15:53 SMTP ERROR: Failed to connect to server: Connection refused (111) 2017-07-21 18:15:53 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting