Want to add a refiner for "Site Title" on SharePoint Online Classic Search Center (as it is not possible to add refiners to SharePoint Online Modern Search "Microsoft Search").
Given is a Hybrid Search Scenario with SharePoint Online and SharePoint 2016 on prem. All results are in one big index. All items from SP 2016 on prem as well as SPO are available in the search results.
Added Crawled Property "ows_sitename" to Managed Property "refinableString00" as you would do on prem as well. Waited 24h.
As added "refinableString00" to the Search Refiner in SharePoint Online it now shows Site Titles to refine -> but just Site Titles from on prem SharePoint. The Crawled Property "ows_sitename" seems to be empty for SharePoint Online results.
Any ideas to accomplish that task or to further debug this to see what's broken?