In several modules of Eventure (when you send an e-mail) it is possible to change the "FROM:" address to your own e-mail address, so it looks like the e-mail is sent by your own mailserver.
However, more and more organizations choose to build in a security step for this, because sending e-mail on behalf of another domain can also be abused.
SPF stands for Sender Policy Framework.
In an SPF record you can describe which servers may send e-mail on behalf
of the domain name. A receiving server can decide on the basis of the SPF
record, to let an email pass, to mark it as unsafe or to reject it.