Call Failure on SendToVRU Node in ICM Script

I would like to share one very interesting observation during one of my UCCE project at one big Telecom Company. During this project everything goes according to plan, except getting call failure on Send to VRU node in ICM scripts, after going through the logs of CVP, I found that gateway is rejecting calls & getting 403 Call Forbidden response in CVP (CVP8 was being used)Logs . After further investigation found out that gateway is rejecting calls because  of toll fraud security settings on gateway.

If toll fraud security  is not configured correctly it will drop untrusted endpoints traffic . Solution is to configure the correct toll fraud security setting otherwise disable IP address trusted list authentication altogether.