# ErrorMessage Error information returned in a change history response when a request fails. ``` object ErrorMessage ``` ## Discussion When a change history request fails, the API populates the `error` field of [`BaseAuditResponse`](/documentation/Apple-Ads-Platform-API/BaseAuditResponse) with an `ErrorMessage`. On success, `error` is null. The `ErrorMessage` object is specific to Change History endpoints and isn’t the same object as the general [`Error`](/documentation/Apple-Ads-Platform-API/Error) envelope used elsewhere in the API. Its `code` is a closed 3-value enum rather than an open string, so `Error`‘s codes (such as `INVALID_ARGUMENT`) don’t apply here. Check the HTTP status code first to determine the error category. Use `code` for programmatic error handling. Use `message` and `details` for diagnostic logging or user-facing error displays. Common error scenarios: - Missing required `eventTime` filter returns `400 Bad Request` - Expired or missing credentials return `401 Unauthorized` - Requesting a `detailId` that doesn’t exist returns `404 Not Found` A `429 Too Many Requests` or `500 Internal Server Error` response also populates `error`. For `429`, see [Applying Rate Limits](/documentation/Apple-Ads-Platform-API/rate-limits) for the headers and backoff strategy to use before retrying. For `500`, retry with backoff since the failure may be transient. ### Example ```json { "code": "BAD_REQUEST", "message": "The eventTime filter is required.", "details": [ { "code": "MISSING_FIELD", "message": "eventTime must be provided.", "info": { "field": "eventTime" } } ] } ``` ## Topics ### Dictionaries [`object ErrorMessage.Details`](/documentation/Apple-Ads-Platform-API/ErrorMessage/Details-data.dictionary) A single error detail entry describing one part of a failed change history request. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)