Enum describing possible field errors.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v26/errors/field_error.proto)

| Enums ||
|---|---|
| ## `BLOCKED_VALUE` | The field's value is on a deny-list for this field. |
| ## `FIELD_CANNOT_BE_CLEARED` | The field cannot be cleared. |
| ## `FIELD_CAN_ONLY_BE_CLEARED` | The field's value cannot be modified, except for clearing. |
| ## `IMMUTABLE_FIELD` | The field attempted to be mutated is immutable. |
| ## `INVALID_VALUE` | The field's value is invalid. |
| ## `REQUIRED` | The required field was not present. |
| ## `REQUIRED_NONEMPTY_LIST` | The required repeated field was empty. |
| ## `UNKNOWN` | The received error code is not known in this version. |
| ## `UNSPECIFIED` | Enum unspecified. |
| ## `VALUE_MUST_BE_UNSET` | The field cannot be set. |