An email can be marked as delivered in Bloomreach and in the ESP (Email Service Provider) logs, while still not appearing in the recipient’s inbox. This means the recipient’s mail server accepted the message, but the mailbox provider—such as Gmail, Outlook, Yahoo, or a company mail server—may have moved it to Spam or Junk, another folder, quarantine, or blocked it.
Solution
If the email is marked as delivered in Bloomreach and in the ESP logs, but you still cannot find it in the inbox, check the recipient’s mailbox or mail infrastructure.
Ask the recipient to check:
Spam or Junk, including Gmail’s Promotions or Updates tabs and Outlook’s Other folder.
Mailbox rules, blocked senders, and safe-sender or allowlist settings.
Company quarantine, security gateway, firewall, or mail-filtering rules.
Whether the mailbox is full and the email application can connect to the mail server.
Mailbox providers may filter emails based on sender reputation, authentication, spam complaints, list quality, sending volume, content, links, and attachments. If several recipients at the same provider are affected, investigate provider-specific filtering; if only one recipient is affected, mailbox or email-client settings are more likely.
Related delivery statuses
If the campaign event shows enqueue_failed, soft_bounced, hard_bounced, or another non-delivered status, this is a separate issue from mailbox filtering. Check the campaign status documentation and the delivery error message to identify the cause. For example, a soft bounce usually indicates a temporary delivery problem, while a hard bounce indicates a permanent failure.
An email may also show as delivered first and then change to a bounce. This is called a delayed bounce: the recipient’s server initially accepts the message with a 250 OK response, but later rejects it during further processing. In Mailgun logs, this is indicated by is-delayed-bounce: true.
Recommendation
To help prevent delivery issues, use the email list hygiene filter and email suppression lists to exclude unengaged, invalid, or unwanted addresses from campaign sends. The email list hygiene filter and custom suppression list don't apply to the Transactional Email API; the global suppression list applies to all email types.
Contacting support
If you need to contact support, include:
The campaign link
The affected customer profile link
The recipient address
Message ID
Timestamps
Final campaign status
Bounce reason
Relevant event details