CampaignExperimentService contain a few
asynchronous operations, the mechanism for fetching errors related to these
operations is different than for other synchronous operations.
The asynchronous operations that use this error reporting mechanism are:
For these methods, the API returns a longrunning
which you can use to request details on the status of the asynchronous
operation. Upon completion, the longrunning operation will populate the
response fields. In the Google Ads API, the operation will always populate the
response with an
Empty value, and the presence of
error will indicate
that a full list of errors can be retrieved from another API call.
If the full list of errors were returned as part of the longrunning operation, then there's a chance the errors might be lost if you don't follow up on the asynchronous progress, and the response may be larger than you might expect from a simple polling request. Therefore, the longrunning operation will only indicate that there are errors, and to fetch the specific errors you must use an API endpoint.
For errors relating to promoting a draft, use
CampaignDraftService.ListCampaignDraftAsyncErrors. Similarly, for errors
relating to creating or promoting an experiment, use
Pass in the resource name of the draft or experiment, and a page size, then page through the results as you would for any other Google Ads API query.