Currently, we can access enterprise tables via Database Authentication but we cannot access via OS Authenticated in Insights.
This is a significant constraint in organizations that only have SQL Server OS authentication for users (many organizations). Microsoft recommends OS Authentication as a best-practice, and discourages the use of individual SQL Server users, when possible due to the security vulnerabilities that this exposes which takes extra layers of security that organizations must provide.
Update: This feature is coming to ArcGIS Insights in our next release - v2020.2 (July 2020).
Retrieving data ...