Permissions on user mail folders

Hi all

I have postfix / dovecot with mysql installed on an Ubuntu 14 droplet. It is listening, ports are open etc.

Tried sending mail from gmail account and I get the following error returned: (I changed domain to someuser@domain.net for public purposes)

This is the mail system at host domain.net.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<someuser@domain.net>: cannot update mailbox /var/mail/someuser for user
    someuser. cannot open file: Permission denied

Final-Recipient: rfc822; someuser@domain.net
Original-Recipient: rfc822;someuser@domain.net
Action: failed
Status: 5.2.0
Diagnostic-Code: X-Postfix; cannot update mailbox /var/mail/someuser for user
    someuser. cannot open file: Permission denied

Permissions of content of /var/mail:

-rw------- 1 vmail vmail  646 Jan 24 14:06 someuser
-rw------- 1 root  vmail 4682 Feb  3 17:53 root
drwxr-sr-x 3 vmail vmail 4096 Jan 24 16:45 vhosts

Any ideas?

Thanks Jacques