Problem: You get a lot of error messages like “Root members not found” or “The call failed on the server”. When examine the log file you find Error 503.
Solution: Typically this is caused by misconfiguration of the OLAP Pump. Open the IIS Manager where you have the OLAP Pump installed, expand Application Pools, right click on your OLAP Pump and select Properties. Then select the tab “Performance”
Idle timeout; typically set the value to 5 minutes (default 20).
Request queue limit; typically set the value to max 65535 (default 1000).
Web garden, Maximum number of worker processes; typically set the value to your number of cores, but not less than 2.