> [!CAUTION]
> **Caution:** This documentation is for Google Ads API **v23** . The latest active version is [**v26**](https://developers.google.com/google-ads/api/reference/rpc/latest/FunctionErrorEnum.FunctionError).

Enum describing possible function errors.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v23/errors/function_error.proto)

| Enums ||
|---|---|
| ## `DATA_TYPE_MISMATCH` | Operand data types do not match. |
| ## `INVALID_ATTRIBUTE_NAME` | Invalid attribute name. |
| ## `INVALID_CONJUNCTION_OPERANDS` | The operands cannot be used together in a conjunction. |
| ## `INVALID_CONSTANT_OPERAND_VALUE` | The value of the constant operand is invalid. |
| ## `INVALID_FUNCTION_FORMAT` | The format of the function is not recognized as a supported function format. |
| ## `INVALID_FUNCTION_FOR_CALL_PLACEHOLDER` | The matching function is not allowed for call placeholders |
| ## `INVALID_FUNCTION_FOR_FEED_WITH_FIXED_SCHEMA` | The matching function is invalid for use with a feed with a fixed schema. |
| ## `INVALID_FUNCTION_FOR_PLACEHOLDER` | The matching function is not allowed for the specified placeholder |
| ## `INVALID_NESTING` | Invalid function nesting. |
| ## `INVALID_NUMBER_OF_OPERANDS` | Invalid numer of Operands. |
| ## `INVALID_OPERAND` | Invalid operand. |
| ## `INVALID_OPERAND_TYPE` | Operand Type not supported. |
| ## `INVALID_OPERATOR` | Operator not supported. |
| ## `INVALID_REQUEST_CONTEXT_TYPE` | Request context type not supported. |
| ## `MISSING_CONSTANT_OPERAND_VALUE` | Missing value for the constant operand. |
| ## `MULTIPLE_FEED_IDS_NOT_SUPPORTED` | The Feed ID was different from another Feed ID in the same function. |
| ## `UNKNOWN` | The received error code is not known in this version. |
| ## `UNSPECIFIED` | Enum unspecified. |