Authenticating Postmark Emails with DKIM
Why are my Postmark emails going to Spam?
If you have a problem with Postmark 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 Postmark emails being blocked is due to the Postmark emails failing DMARC, which in the case of Postmark, is usually due to a misconfiguration of DKIM.
How to stop Postmark emails going to Junk.
The first step to preventing Postmark 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 Postmark emails from going to spam, or at least rule out authentication as the issue.
How to remove 'via postmarkapp.com' or 'on behalf of postmarkapp.com'
Another example of where a Postmark DKIM misconfiguration is to blame, is if your recipients report seeing the message as 'via postmarkapp.com' or 'on behalf of postmarkapp.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 Postmark by logging in to your Postmark account to check to see if you have followed the following article to configure your Postmark dkim setup to authenticate your domain.
How to stop Postmark Failing DMARC
To ensure that your Postmark 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 Postmark DKIM keys. However, in order for Postmark email to pass authentication for your own domain, it is necessary to use your own DKIM keys as per Postmark's own guide. If you wish to verify the above, paste the message headers for a failed Postmark message into our Postmark email testing tool