Issue Updating Budget via API: “The billing setup is not eligible for budgets”

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Dear Google Ads Support Team,

I encountered an issue when attempting to update the budget for one of our accounts via the Google Ads API.
The API returned the following error message:

“The billing setup is not eligible for budgets.”

The affected account ID is 4399954873, and the requestId is qtCl8o0MT3wXfIuGbObgNw.

Could you please help clarify what this error means?
Is there a specific configuration in the account’s billing setup that needs to be adjusted in order to make the budget eligible for updates through the API?

Any guidance you can provide would be greatly appreciated.

Thank you for your support.
Best regards,