Cannot see failed report into ExecutionLogStorage

Hi,

We installed SQL Server Reporting Services 2012 (in native mode) and since this installation we cannot see other status thanrsSuccess by querying ExecutionLog2.

Is there a setting somewhere to see all reports and there status, especially with errors like RsAccessDenied?

I'm searching info to activate higher level of logging without any success.

Note that "Enable report execution logging" is checked and ExecutionLogLevel is set to Verbose as suggested here.

Thanks by advance for your help :)