I'm trying to retrieve conversion value (total purchase data) for my Facebook Ads campaigns using the Facebook Ads Insights API. However, when I include the omni_purchase field in the fields parameter at the account level (level=account), I receive an error message: "omni_purchase is not valid for fields param."

=act_12600000000/insights?&level=campaign&time_increment=monthly&fields=account_name,account_id,impressions,clicks,outbound_clicks,conversions,conversion_values.

The metrics i want to get on the ads manager :

• Purchases with Shared Items
• Purchases conversion value for shared items

But i cannot get this on graph API. If anyone knows the answer, please suggest it. Furthermore, i use third-party tool to get API like supermetric or windosr.ai i can get this data