Authenticating Zimbra Emails with DKIM
Why are my Zimbra emails going to Spam?
If you have a problem with Zimbra emails going to spam, that is, going to the junk folder of your recipients, then it is very likely an issue with your email authentication. Emails failing authentication, be they failing SPF, failing DKIM, or failing DMARC is common, as SPF, DKIM, and DMARC are often not properly implemented by domain administrators. Often, the main cause of Zimbra emails being blocked is due to the Zimbra emails failing DMARC, which in the case of Zimbra, is usually due to a misconfiguration of DKIM.
How to stop Zimbra emails going to Junk.
The first step to preventing Zimbra email going to spam is to retrieve a failed message and access its header information. This will allow you to quickly diagnose whether any authentication issues such as DKIM or DMARC are flagging your email as spam, instructing the recipient sender to move it to junk. Simply paste the email headers into our free Stellastra Deliverability Tool, which you can use freely with no log in required. Our deliverability tool should allow you to avoid Zimbra emails from going to spam, or at least rule out authentication as the issue.
How to remove 'via zimbra.com' or 'on behalf of zimbra.com'
Another example of where a Zimbra DKIM misconfiguration is to blame, is if your recipients report seeing the message as 'via zimbra.com' or 'on behalf of zimbra.com' and that the emails typically end up in spam or junk. The Stellastra Email Deliverability tool above will confirm this prognosis, however, you may also wish to configure DKIM for Zimbra by logging in to your Zimbra account to check to see if you have followed the following article to configure your Zimbra dkim setup to authenticate your domain.
How to stop Zimbra Failing DMARC
To ensure that your Zimbra campaigns pass DMARC and get delivered to your prospects, it is important to ensure that DKIM passes authentication for your domain. A common mistake is to sign an email with Zimbra DKIM keys. However, in order for Zimbra email to pass authentication for your own domain, it is necessary to use your own DKIM keys as per Zimbra's own guide. If you wish to verify the above, paste the message headers for a failed Zimbra message into our Zimbra email testing tool