Configuring SMTP Module

Hello,

Our Dolphin is 7.0.9 and PHP 5.3 www.e-som.net/comunidades.

We´re having problems to configure this module. 

We want to know if we have to do some change in our codes. emails with @e-som.net or @our_company don´t properly delivery. We observe that @hotmail.com or @gmail.com is ok!

Somebody to help us?this is happening  after we did the upgrade 7.0.5 to 7.0.9. 

Thanks in advance.

We made various test and our server is able . But Dolphin don´t recognize .

****See the message below when "Alfa" request for friend with "nuriah" :

SMTP Error: Could not connect to SMTP host. 
Warning: Cannot modify header information - headers already sent by (output started at /home/educacao/public_html/comunidadenova/plugins/phpmailer/class.phpmailer.php:586) in /home/educacao/public_html/comunidadenova/communicator.php on line 179

****When "Alfa" send a message to "nuriah" she receives this message below:

SMTP Error: Could not connect to SMTP host. SMTP Error: Could not connect to SMTP host. SMTP Error: Could not connect to SMTP host. 
Warning: Cannot modify header information - headers already sent by (output started at /home/educacao/public_html/comunidadenova/plugins/phpmailer/class.phpmailer.php:586) in /home/educacao/public_html/comunidadenova/mail.php on line 317