AI-generated Key Takeaways
- 
          InventoryTargetingError.Reason provides reasons for target errors within various services like AdRuleService and ForecastService. 
- 
          Reasons include issues such as requiring at least one placement or inventory unit, conflicts between targeted and excluded inventory, and limitations based on ancestor targeting or exclusion. 
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          Constraints also exist regarding self-only inventory units and targeting YouTube audience segments with specific inventory. 
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          The value "UNKNOWN" is returned if the actual error reason is not available in the API version. 
The reasons for the target error.
- Namespace
- 
               https://www.google.com/apis/ads/publisher/v202508
| Enumeration | Description | 
|---|---|
| AT_LEAST_ONE_PLACEMENT_OR_INVENTORY_UNIT_REQUIRED | At least one placement or inventory unit is required | 
| INVENTORY_CANNOT_BE_TARGETED_AND_EXCLUDED | The same inventory unit or placement cannot be targeted and excluded at the same time | 
| INVENTORY_UNIT_CANNOT_BE_TARGETED_IF_ANCESTOR_IS_TARGETED | A child inventory unit cannot be targeted if its ancestor inventory unit is also targeted. | 
| INVENTORY_UNIT_CANNOT_BE_TARGETED_IF_ANCESTOR_IS_EXCLUDED | A child inventory unit cannot be targeted if its ancestor inventory unit is excluded. | 
| INVENTORY_UNIT_CANNOT_BE_EXCLUDED_IF_ANCESTOR_IS_EXCLUDED | A child inventory unit cannot be excluded if its ancestor inventory unit is also excluded. | 
| EXPLICITLY_TARGETED_INVENTORY_UNIT_CANNOT_BE_TARGETED | An explicitly targeted inventory unit cannot be targeted. | 
| EXPLICITLY_TARGETED_INVENTORY_UNIT_CANNOT_BE_EXCLUDED | An explicitly targeted inventory unit cannot be excluded. | 
| SELF_ONLY_INVENTORY_UNIT_NOT_ALLOWED | A landing page-only ad unit cannot be targeted. | 
| SELF_ONLY_INVENTORY_UNIT_WITHOUT_DESCENDANTS | A landing page-only ad unit cannot be targeted if it doesn't have any children. | 
| YOUTUBE_AUDIENCE_SEGMENTS_CAN_ONLY_BE_TARGETED_WITH_YOUTUBE_SHARED_INVENTORY | Audience segments shared from YouTube can only be targeted with inventory shared from YouTube for cross selling. | 
| UNKNOWN | The value returned if the actual value is not exposed by the requested API version. |