how to send mails in php using exchange server using smtp server configuration

Question

i have created mail server in exchange server 16 and i am trying to connect using smtp server

smtp port : 25 or 587 smtp server: smtp.xxx.mail.mil

i have written complete code using php mail function but

if(mail($to,$subject,$message,$headers))
    {
        echo "Mail Send Sucuceed";
    }
    else{
        echo "Mail Send Failed";    
    }

The code works fine for gmail but doesnt work with exchange. Any one can help me with the correction or alternative also i want to send mail in a particular lab network which is created.