Nowadays, with so much volume of spam clogging the email pipes of the internet, deliverability is becoming a serious problem. Much legitimate messaging gets routed to spam buckets without having a chance to be seen by the intended recipient. Sender Policy Framework is a standard created to improve things, by allowing domain name owners to specify which servers are authorized to send messages in their behalf. If you'd like to learn more about it, we recommend this link: http://www.openspf.org/Introduction
To maximize the chances of your email reaching your subscribers, we recommend you give us explicit authority to send email for your domain. This is done by adding "include:localharvest.org" to your SPF record in your domain's DNS configuration. Your SPF record will then look something like this:
v=spf1 ip4:x.x.x.x include:localharvest.org -all
Replacing the x.x.x.x string above with whatever the IP address or range from where your domain usually sends email.
For more information and details on this, we suggest you contact your website / DNS provider.