How to invoke UI path robot using WCF/ .net application

I tried to write a WCF to invoke the robot from a .net application. WCF function is working fine and calling the UIPath bot. Unfortunately the bot not taking the input and performing the required action. I am getting the below error as access denied. Checked the permissions, I am running it in my local and have the admin access to run the WCF service. This is the error which I am getting.

{“message”:“Executor start process failed, reason System.UnauthorizedAccessException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))\r\n at UiPath.UiSystemClass.OpenInteractiveWindowsSession(String bstrUser, String bstrPassword, UiOpenSessionFlags nFlags, String bstrApplication, String bstrAppArguments, Int32 nDelayMs, Int32 userToken, UiGenericOptions options)\r\n at UiPath.Core.Setup.OpenInteractiveWindowsSession(String username, String password, OpenSessionFlags flags, String application, String arguments, Int32 userToken, Int32
preferredWidth, Int32 preferredHeight, Int32 preferredDepth)\r\n at UiPath.Service.Impl.Executor.StartProcessInSession(Guid executorInstanceId, String username, String password, SettingsDictionary execSettings, IntPtr userToken)\r\n at

Need to know about the API is available/open to run the bot using WCF.