I have SharePoint 2013 + SQL Server 2012 SSAS Tabular Mode + SSRS running in SharePoint integrated mode for business intelligence reports. This is in 2 environments, QA and PROD, which are identical AFAIK. All Reporting Services/PowerPivot/Power View services appear to be running in SharePoint.
Power View reports have worked fine for a couple years. However, the PROD environment recently stopped working for Power View reports. If I click on a .bism or .rdlx file, it tries to open the Power View screen (_layouts/15/ReportServer/AdHocReportDesigner.aspx), but then it shows "Server cannot be found. Please contact your administrator". I have enabled verbose logging on SQL Server Reporting Services, and PowerPivot in SharePoint's ULS logs. I then generated the error, and it displays nothing helpful in the logs.
Everything else seems to work okay, including Excel files containing PivotTables connected to the same SSAS data source that the Power View reports are struggling with. How can I do further troubleshooting? I have checked SQL Server logs, ULS logs, Windows Event logs and have not found a single clue for why "Server cannot be found".