The attempt to connect to the report server failed. Check your connection information and that the report server is a compatible version.
I ran into this issue and was happy to find this solution. Thought of sharing this fix and also for my future reference purpose.
Error: The attempt to connect to the report server failed. Check your connection information and that the reportserver is a compatible version.
Found the below error message in the SSRS log file located at C:\MSSQL\MSRS10_50.MSSQLSERVER\Reporting Services\LogFiles.
e ERROR: RsHttpRuntime::VerifyAuthMode(): caught exception System.Configuration.ConfigurationErrorsException: The value of the property 'mode' cannot be parsed. The error is: The enumeration value must be one of the following: None, Windows, Passport, Forms. (C:\MSSQL\MSRS10_50.MSSQLSERVER\Reporting Services\ReportServer\web.config line 9)
I changed the authentication option to Windows (Previously it was none) in web.config file (located at C:\MSSQL\MSRS10_50.MSSQLSERVER\Reporting Services\ReportServer)and restarted the SSRS service which fixed the issue.
Now users are able to browse the SSRS service.