https://support.microsoft.com/en-us/topic/kb3162396-fix-shared-data-sources-and-stored-credentials-are-removed-by-the-sharepoint-daily-cleanup-jobs-in-ssrs-576247af-4613-d714-b529-2a26d7034e1a
KB3162396 - FIX: Shared data sources and stored credentials are removed by the SharePoint daily...
Fixes an issue in which shared data sources and stored credentials are removed by the SharePoint daily cleanup jobs in SQL Server Reporting Services.