Mailer issue

Dear all,

I setup mailer in the globals, and i am using gmail. I create a server action end i add a step for sending email. I can send successfully the email, but after the mail server logs i am receiving in the response , the following errors:

Can somebody assist me on this ?

<b>Fatal error</b>
:  Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /var/www/html/dmxConnectLib/PHPMailer/PHPMailer/SMTP.php:277) in /var/www/html/dmxConnectLib/dmxConnect.php:86
Stack trace:
#0 [internal function]: exception_error_handler(2, 'Cannot modify h...', '/var/www/html/d...', 86, Array)
#1 /var/www/html/dmxConnectLib/dmxConnect.php(86): header('HTTP/1.1 500 In...')
#2 [internal function]: exception_handler(Object(ErrorException))
#3 {main}
  thrown in 
<b>/var/www/html/dmxConnectLib/dmxConnect.php</b>
 on line 
<b>86</b>
<br/>
<br/>
<b>Fatal error</b>
:  Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /var/www/html/dmxConnectLib/PHPMailer/PHPMailer/SMTP.php:277) in /var/www/html/dmxConnectLib/dmxConnect.php:47
Stack trace:
#0 [internal function]: exception_error_handler(2, 'Cannot modify h...', '/var/www/html/d...', 47, Array)
#1 /var/www/html/dmxConnectLib/dmxConnect.php(47): header('HTTP/1.1 500 In...')
#2 [internal function]: fatal_handler()
#3 {main}
  thrown in 
<b>/var/www/html/dmxConnectLib/dmxConnect.php</b>
 on line 
<b>47</b>
<br/>