A recipient is identified as bounced when email can't be delivered to them. Bounces can be categorized into hard bounces and soft bounces.
Hard Bounces
Indicates a permanent error for email deliverability. The most common reason for hard bounces is when you try to send to an invalid email address. To protect your sender reputation, OnVoard automatically excludes hard bounced email addresses from all future emails.
Soft Bounces
Indicates a temporary error for email deliverability. Below are some common soft bounce reasons.
- Message temporarily rejected by mailserver to prevent spam. (This is the most common reason)
- Recipient inbox is full.
- Recipient email server is offline.
- Email can't be relayed due to connectivity reasons.
- Inbox provider temporarily delaying messages from untrusted senders to prevent spams.
- Email message is too large.
- Email message blocked due to detected spam content.
Keep in mind that in some cases, a recipient may initially encounter a temporarily delayed soft bounce error before receiving a successfully delivered email. The following timeline will explain this scenario.
- At 2am, we attempt to send email to
john@example.com john@example.cominbox provider temporarily delays receiving of message. This is sort of like in pending mode. The message was not blocked or rejected. Sometimes inbox providers do this to cap the number of deliveries from untrusted senders to prevent spams.- We will mark the recipient as soft bounced due to temporary issue.
- At 5am, inbox provider notified that email has been successfully delivered. We will mark recipient with successfully delivered email.