So some time to tinker...
@kris, Good to hear kris let me know what you did to make things working.
@Tim, Tim i suppose it was late when you read my message.

My mail sever isn't running. I think i forget something to make things work. The settings i have:
SMTP Server
- Settings
Domain: mydomain.eu
Hostname: mail.mydomain.eu
Relay Host: (empty)
Maximum Message Size: 50MB
- User Policies
SMTP Authentication Enabled
- Destinations Domains
(empty)
- Trusted Networks
(empty)
- Mail Forwarding
(empty)
Zarafa Community
Zarafa Delivery Agent Running
Zarafa iCal Gateway Running
Zarafa POP/IMAP Gateway Running
Zarafa Quota Monitor Running
Zarafa Search Indexer Running
Zarafa Spooler Running
Zarafa Storage Server Running
System --> mail settings
Mail Domain: mydomain.eu
I've checked and port 25 is open.
Also I've created a MX record: mydomain priority 10 mail.mydomain.eu.
When i make a mail at gmail and use my mail address to send it to the mail never arrives. What I'm doing wrong?