As per the technote of IIS v11.5 the metadata bridge (Microsoft SQL Server Analysis and Reporting Services (Repository) bridge reference) doesn't support SQL Server 2014.
However, while using the IIS v11.5.0.1 there is an additional option of selecting the SQL Server v2014.
Could someone please verify whether the IIS v11.5.0.1 supports the reporting services of SQL Server v2014 or not?
SQL Server 2014 is supported in 115 fix pack 2. Please install the latest fix pack to have it supported.