When making ID Sync calls, if a portion of the call is empty, an error 300 will be returned in the Audience Manager response. For example, if we have a datasource ID 123456 with the integration code of “customer_id” but the actual declared id isn’t being passed it will resemble the following:
There should be a value between each of the %01 codes, as that is where the passed or declared id is expected.
Because no value is being passed, when the Audience Manager response is returned you will see the “300” error:
“msg”: “Invalid customer id 123456:”
Ensuring that the declared id is being passed into the request will resolve the error and enable the proper syncing of the desired ids.
If there are additional questions about formatting the ID Sync calls, please refer to the AAM product documentation at https://experienceleague.adobe.com/docs/audience-manager/user-guide/features/declared-ids.html?lang=en#variables-and-syntax.