Starting March 17, 2025, the CustomerService.CreateCustomerClient method in the Google Ads API will be updated to align with how the Google Ads UI handles new account creation. These changes aim to improve policy enforcement and prevent abuse.
The upcoming API v19 introduces new error codes related to policy compliance. Manager accounts that do not meet a certain spending threshold or have policy-related issues, such as suspended or closed accounts, will be unable to create new child accounts.
Read the official announcement here: Upcoming changes to CustomerService in Google Ads API.
