Populated only on message.failed.
| Name | Type | Description | Notes |
|---|---|---|---|
| Code | int | [optional] | |
| Title | string | [optional] | |
| Message | string | [optional] | |
| Explanation | string | Plain-language translation of `code` (e.g. for 131026, that the recipient has likely opted out of marketing messages while utility templates are unaffected). Null for unmapped codes; fall back to title/message. | [optional] |