If you are not sending your email out via the server where your domain name resides, some web hosts will reject the email as being sent via a different server and is therefore considered likely Spam. The easy fix for this is to always send your outgoing mail for your QiQ hosted domain via the QiQ web server. That way, the IP Address associated with your email address will match and any site that uses the SPF system will accept your email.
To do this, simply make sure your SMTP address is set to mail.your-domain.com Whilst there is an alternative for us to add the extra IP addresses you send mail via to the SPF record, this is not easy as most ISPs generate a new IPS address when you log in, so it would be forever changing.
For further details please refer to http://www.openspf.org/.