When you send out email campaigns via MailerLite, you might notice that you don't receive out-of-office (OOO) replies from your subscribers. Don’t worry, this isn’t an error. In fact, it’s intentional.
The “Precedence: Bulk” header
MailerLite, like many bulk emailing services, includes a special header in each email sent out as part of a campaign. This header is known as Precedence: bulk.
When this header is included, many email providers — particularly consumer email services like Gmail — automatically suppress automatic response messages such as out-of-office notifications. Some business email platforms (such as Microsoft Exchange or Outlook-based systems) may still send OOO replies if your campaign has a Reply-to address set. So while OOO replies are suppressed by many providers, you may still receive some from business email accounts depending on their configuration.
Keep in mind, the Precedence: bulk header does not negatively affect how your emails are treated by email providers. It does not lead to your emails being marked as spam or pushed to the Promotions tab. In fact, it helps email providers understand your intent to send bulk emails, which can improve how your emails are handled.