Hello @Casepoint Developer
Thanks for reaching out!
Currently Site resource does not expose owner property. Per my understanding, the endpoint you are using to list sites created by a specfic user is not valid.
Additionally, as per Search for sites documentation, the Search filter is a free text search that uses multiple properties when retrieving the search results. It searches for relevant sites which matches the keywords provided.
However, to know the owner of a specific site, you could use this workaround:
You can get the default library owner in the site. The default library owner would be the site owner. Below is the endpoint to get the sites drive, there is an owner property in the response:
GET https://graph.microsoft.com/v1.0/sites/{site-id}/drive
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Hope this helps.
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