Undeliverable messages - commonly called bounces - are processed automatically by Reachmail and are available by category in the bounce detail section of any individual mailing report.
Rows in blue indicate bounce types which are automatically deactivated. In the case of hard bounces, only a single failure is required for a deactivation.
| Bounce Type | Code | Description |
| Auto Reply | AR | An automatic response from the recipient. Examples: "Out Of Office", "Vacation Message" |
| Bounce - No email address | B | Message was a bounce, but ReachMail could not resolve the original email recipient email address. Rare. |
| Challenge-Response | CR | Challenge-Response email systems were created as a reaction to the increasing circulation of spam. |
| General Bounce | GB | The email server could not deliver your email message, but the bounce message was unclear as to what kind of bounce it was. ReachMail treats these as soft bounces in general mailing reports. Example: "Subject: Undeliverable mail" |
| Hard Bounce | HB | The email server could not deliver your email message. Example: "550 User Unknown" |
| Mail block - General | MB | Indicates that the recipient's email server is blocking email from your email server. Example: "550 Message REFUSED by peer" |
| Mail block - Known Spammer | MBKS | Indicates that the recipient's email server is blocking email from your email server because it believes you are a known spammer. Example: "REJECT Known SPAM source" |
| Mail block - Content | MBSD | Indicates that the recipient email server is blocking email from your email server because the message appears to have atypical content. |
| Mail block - Attachment Detected | MBAD | Indicates that the recipient's email server is blocking email from your email server because the email message contained an attachment. Example: "552 Disapproved attachment" |
| Mail block - Relay denied | MBRD | Indicates that the recipient's email server is blocking email from your email server. Example: "551 relaying denied" |
| Non bounce | NB | The message was not a bounce. This could be a recipient reply, or maybe a bounce format that ReachMail did not recognize. |
| Soft bounce - General | SB | The email server is temporarily unable to deliver your message to the recipient email address. Example: "Connection timed out." |
| Soft bounce - DNS failure | SBDF | The email server is temporarily unable to deliver your message to the recipient email address because of a DNS issue. Example: "Host is unreachable" |
| Soft bounce - Mailbox full | SBMF | The email server is temporarily unable to deliver your message to the recipient email address because the recipient's email box is full. Example: "Mailbox over quota" |
| Soft bounce - Message size too large | SBMSTL | The email server could not deliver your message to the recipient because the message size is too large.
Example: "Exceeded maximum inbound message size" |
| Soft Bounce - Retries Exceeded | SBRE | The email server was not able to deliver your message despite repeated attempts over an extended period of time. This is usually due to the remote system awaiting positive engagement metrics. |
| Subscribe request | SR | Someone is requesting to be added to your opt-in email list. ReachMail looks for subscribe requests in the subject header of the email message, and on the first line of a text based email message. ReachMail parses for subscribe requests in several different 7-bit ascii languages. (ie. English, Spanish, French, German, etc.) |
| Transient bounce | TB | ReachMail temporarily can not deliver your message, but it is still trying. Example: "Warning: message still undelivered after 4 hours. Will keep trying until message is 2 days old" |
| Unsubscribe request | UR | Recipient is requesting to be removed from future email from you. ReachMail looks for unsubscribe/remove requests in the subject header of the email message, and on the first line of a text based email message. ReachMail parses for unsubscribe requests in several different 7-bit ascii languages. (ie. English, Spanish, French, German, etc.) |