"HTTP 503: Service unavailable" error when you open the SSRS web portal after you upgrade to SSRS 2016 Content provided by Microsoft Applies to: Microsoft SQL Server 2016 DeveloperMicrosoft SQL Server 2016 EnterpriseMicrosoft SQL Server 2016 Standard Select Product Version All ProductsMicrosoft SQL Server 2016 StandardMicrosoft SQL Server 2016 DeveloperMicrosoft SQL Server 2016 Enterprise Symptoms You upgrade an earlier version of SQL Server Reporting Services (SSRS) to SSRS 2016. When you open the SSRS web portal, you receive the following error message:HTTP 503: Service Unavailable Resolution The fix for this issue is included in the following cumulative update for SQL Server:Cumulative Update 1 for SQL Server 2016 About cumulative updates for SQL ServerEach new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:Latest cumulative update for SQL Server 2016 Status Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. References Learn about the terminology that Microsoft uses to describe software updates. Last Updated: Jan 7, 2017 Did this solve your problem? Yes No Tell us what we can do to improve the article Submit Thanks! Your feedback will help us improve the support experience.