Fresh Plesk installation not sending mail

Hi everyone,

I have an issue with my fresh plesk installation with Debian 8.
All my mails are not sending from my domains. I think that I have a misconfiguration of postfix service but I'm not sure.

I can receive emails and send to local mail adresses but when I try to send mail to external mails nothing is sent and all emails are stored in Queue. The logfile display a lot of "Connection time out" messages.

Thank you for your help!

Here is my postfix main.cf file :

# See...

Fresh Plesk installation not sending mail