Hello,
If you are looking to replicate the "Start with a Website" part of the Keyword Planner using the API, then I'm afraid it's not possible. If you want to use keywords and urls, you can include them in your
request. If you are still facing issues, please
reply privately to author your API request and response so I can take a closer look.
Thanks,
Anthony
Google Ads API Team

ref:_00D1U1174p._5001UZXc5T:ref