Meaning of Bounce Messages

Bounce messages are sent back to CleverReach by the receiving servers should an email not be delivered. These messages vary even though in principal they all point out that an email could not be delivered. Here is an overview of the most common bounce messages:

Incorrect Address

host is unknown / host not found
invalid adress / invalid recipient
mailbox not found / mailbox is unavailable
no mailbox here by that time
no such user
recipient e-mail adress unknown
user unknown / unknown user
said: 550

Filtering by Receiving Server

mail was identified as spam
only registered users may use this system
recipient adress rejected
relay not permitted

Hardware Issues on Receiving Server

error writing message
message could not be stored
relay access denied

Mailbox Issues

mailbox does not exist
mailbox has been deactivated / disabled / discontinued
mailbox is full
mailbox unavaliable
user has exhausted allowed storage space

The messages said: 550 and said: 553 are used by some servers to classify bounced emails as spam. Basically every server can send custom bounce messages and there is no ONE standard. The overview above represents the most common bounce messages known to us.

We recommend reading the linked page to optimize deliverability of your emails.

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