Prevent emails going into spam folders
If you find that emails are being filtered into a spam folder, or junk mail folder, the first thing to check is the SPF record of your domain name.
For example, if you are sending emails from the email address email@example.com, you should check the SPF record for the domain name example.com by searching for spf:example.com at the MXToolbox website. The 'spf:' before your domain name is essential for that search.
See here for how to check and adjust your SPF record.
Once your SPF record is sorted out, there are other things to check for:
- Make sure that you have added all of your domain names to the Sender Domains page, and check they are all verified.
- Create a free account at Google Postmaster Tools. This will give you the ability to see various metrics that Google/Gmail keeps for your domain name and will let you see if there is a problem. Note: it will take a few days for any stats to appear after you create an account with them.
- Make sure that you are sending to an "opt-in list". You must never send emails to a purchased email list or email addresses harvested from the internet. You must be able to directly verify when and where each contact subscribed.
- If you're sending from a free email service such as Hotmail, Yahoo, etc. your emails are often treated more suspiciously by recipient spam filters. It is always better - and more professional - to send emails from your own (or your business') domain name. You should never send emails from a Yahoo or AOL email address (as of April 2014) as these domains are now restricted by their DMARC policies. You should also not send from a Gmail email address as of June 2016 due to Gmail's new DMARC policy.
- If you place links in an HTML email, it is best to not display the actual link (http://www.etc...) in your email. Many email programs now have anti-phishing technology which treats such links suspiciously. If the underlying URL of your link is different from the URL displayed, then your email will be marked as spam by email clients such as Thunderbird. And never use an IP address in a link.
- Never use URL shorteners in an email.
- Check that your domain name isn't on a domain blacklist. We automatically check all IP-based blacklists, however you may find one of your domain names has become listed on a domain-based blacklist. You can search for your domain name at MXToolbox.
- Continuing with the topic of domain reputation, search for your domain name at BorderWare Watchguard. This will show BorderWare's assessment of the reputation of all IP addresses that are sending emails from your domain name. Any servers that have a bad reputation may have become compromised, or may be sending out emails that have generated spam complaints in the past, and should be investigated. You can do a similar search for your domain name at SenderScore.org.
- If you send both promotional mail and transactional mail relating to your organization, we recommend separating mail by purpose as much as possible. You can do this by using separate email addresses for each purpose, or sending mail from different domains.
- You can run your email through a series of checks by using the IsNotSpam email checker. You'll be able to view a report that will let you know how SpamAssassin (a popular spam filter) assesses your email, and if your SPF and DKIM record is setup correctly.
- Don't send emails from a brand new domain name. The domain name used in your 'From' email address should ideally already have a good email sending history, and be older than just a few months. This also applies to domain names used in the links contained within your emails.