Hello,
Thanks for reaching out. Looking into the account,
331-873-5866, I see that it only has one
pre-registration app campaign. This campaign type is not currently supported in the Ads API, which would explain why you received an empty response. However, support for this campaign type has been requested previously. If support for this campaign type is added, it will be announced on
the blog.
Regards,
Matt
Google Ads API Team

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