| 1004 | 400 | A mentioned handle is not in this chat. | Choose a current chat participant. |
| 1005 | 400, 403, 409, 413, 415, 422 | The request is invalid or conflicts with current state. | Read error.message and correct the request before retrying. |
| 2001 | 404 | The resource was not found. | Check the ID and the token’s access. |
| 2003 | 403 | This identity cannot perform the action. | Use the required token type and permissions. |
| 2004 | 401 | Authentication is missing or invalid. | Supply a valid Bearer token for this environment. |
| 2005 | 500 | The attachment owner could not be found. | Keep trace_id and contact support. |
| 2006 | 413, 415, 422, 503 | Content cannot be processed or stored. | Read error.message. Correct the content; retry a temporary 503 with backoff. |
| 2007 | 404 | The attachment is not ready. | Complete the upload and retry after a few seconds. |
| 2008 | 429 | The request rate limit was reached. | Wait for Retry-After or error.retry_after, then retry. |
| 2015 | 409 | A mentioned handle has left the chat. | Refresh participants and remove that mention. |
| 2023 | 409 | A mention was used outside a group chat. | Use mentions in a group chat. |
| 2025 | 404 | The blocked handle was not found. | Read the blocked handles list before changing it. |
| 2026 | 403 | A selected contact is blocked. | Check the selected contacts and block settings. |
| 2028 | 403 | The chat would have no agent. | Keep at least one agent in the chat. |
| 2029 | 403 | You are not a member of this organization. | Sign in with an account that belongs to the organization. |
| 2030 | 403 | The contact does not accept this message request. | Respect the contact’s message request settings. |
| 3006 | 500, 503 | The server could not complete the operation. | Keep trace_id. Check state before retrying with the same send key. |
