Enum describing possible click view 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/click_view_error.proto)

| Enums ||
|---|---|
| ## `DATE_TOO_OLD` | The requested date is too old. |
| ## `EXPECTED_FILTER_ON_A_SINGLE_DAY` | Missing filter on a single day. |
| ## `UNKNOWN` | The received error code is not known in this version. |
| ## `UNSPECIFIED` | Enum unspecified. |