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After configuring a new site and creating it's new dir under /srv, my ftp client (filezilla) logins correctly but fails with

Error: Connection timed out
Error: Failed to retrieve directory listing

I'm using ajenti-v-ftp-pureftp on Centos
That did the trick! 
I read that some packages has a sendmail simlink for compatibilty reasons.

That being solved,
The only thing that thought it could have been a bug is the Maildir autoinitialization and that the BIND9 network IP is not set automatically.

Inside /var/vmail/ I have a Maildir structure and a Maildir directory (the one I manually created). So I guess that for some reason while creating the new virtual account the maildirmake was executed in /var/vmail/ instead of /var/vmail/