First find the message under Notifications. Its status tells you whether the problem occurred before sending or after the receiving mail service accepted it.

Scheduled or queued

Check these conditions:

  1. The requested variant is currently available in Shopify.
  2. Settings → Store information contains a complete business address.
  3. Your plan still has notification email allowance available.
  4. The recipient address appears valid.

Slingshot can hold a message rather than sending incomplete or invalid email.

Failed

Open the notification and review the visible failure reason. Common causes include an invalid recipient, a rejected sender/domain, or a temporary provider error. Do not repeatedly retry a permanently invalid address.

Sent but not received

Sent means the recipient’s mail service accepted the message. Ask the recipient to search for your sender name and check Spam, Junk, Promotions, quarantine, and company filtering. Delivery reporting can take time.

Test the scope

Send a test notification to a different provider, such as a second personal inbox. One affected domain suggests recipient-side filtering; many unrelated domains suggest a broader issue.

Paid-plan support requests should include notification IDs or timestamps, affected recipient domains with addresses redacted, current status, and whether test emails work.