Just encounter a problem on SQL Server Reporting Services after installation SQL Reporting on SCOM Server. When perform a test on URL http://servername/ReportServer it displayed below error message:
Based on the information found in this link, it mentioned that SQL reporting failed to initialize due to unmatched installation identifier and public key.
1. Open Reporting Services Configuration Manager
2. Go to Encryption Key and select Delete
3. Test again. By right, you should be able to get Reporting Server initialize and working fine.