There is an issue with outgoing e-mail and reverse DNS that results in some mails not being delivered (instead you get a message that the e-mail recipients server would not accept the e-mail since reverse DNS did not work).
We are working on a solution (i.e. getting the reverse DNS working), in the meantime the workaround solution is to either use your ISP's outgoing relay SMTP server (e.g. in Sweden, Telia will effectively block any attempts to send e-mail with anything else than their relay SMTP server) or to use the ability of Gmail to send with a different e-mail address than your Gmail address, see the settings of your Gmail account (we're producing an howto on the subject of jaerto e-mail with Gmail too, coming soon!). On a side note, it is also possible to use Gmail for incoming e-mail to your account at jaerto, this in set up in the same place.
Setting up sending in Gmail, look under settings for this place:
