How to Send Email via a Postmark SMTP Server

You can set up a custom SMTP server such that Prefinery emails are sent to your users through your own SMTP server, and not through Prefinery's servers.

Please note that using a custom SMTP server will change which email metrics Prefinery can track for you. When using a custom SMTP server, we can no longer track clicks, bounces and spam complaints. However, we will continue to track email opens and unsubscribes.

To add a Postmark SMTP server, follow these steps: 


Click on the Email link in the left-hand sidebar and then on Addresses. Add the email address from which you will be sending your email campaign. 

Be sure to confirm this email address by clicking the confirmation link that we send you via email. You do not need to verify this domain if you will be using your own SMTP server.


In Postmark, be sure to add the same email address you added to Prefinery in step #1, above, to Postmark as a Verified Sender by following this Postmark guide

When you created your Postmark account, they will automatically send you a Sender Signature verification message to the address you used to sign up. They will arrive from Postmark and look like this: 

If you need to add or use a different address (perhaps the one you want to use in your Prefinery project isn't added yet in Postmark), you can add those from Sender Signatures

Continue to step 3 of the mentioned Postmark guide (Authenticating with DKIM, SPF, and DMARC). 

Once you reach step 4 in the guide, as described in their Sending email with SMTP documentation, go to the Settings tab of your Outbound Stream to get your SMTP token. 

With an SMTP token, the Access Key acts as the username and the Secret Key acts as the password that you'll use in the next step. 


Back in your Prefinery project dashboard, go to  Settings > Project Settings > Custom SMTP Server then turn ON the feature. 


In the provided input boxes, enter your SMTP server credentials. For Postmark, you will need to specify the following: 

Port: 587
Authentication: Cram MD5
User name: <SMTP Token Access Key>
Password: <SMTP Token Secret Key>
TLS: Checked

Once you click Save you will see a Testing Connection message while a test email is attempted to be sent to you via your Postmark SMTP server from the address you added in steps 1 & 2. 

If the connection fails, be sure to double-check the credentials you added in step #4 and be sure that you have added the sender email address to Postmark, as specified in step #2. 

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