Cognitive Search for Azure OpenAI does not work for custom app developed using ASP.net C# MVC code

Question

Hello Experts,

I have developed an app using ASP.Net C# MVC web app in which I have used Azure OpenAI ChatCompletions. This web app has been deployed as an Azure App Service WebApp.

I have the below 2 questions:

1. When I try to create a custom data source within Azure OpenAI studio and deploy the web app, it does not recognize the existing web app that I created. On the other hand, it only recognizes the app created from with the AI studio. Why?
2. I have used the Azure OpenAI endpoint and Key within my code and the code runs, but it never brings the results back from the custom data source that I created, i.e., it never brings the data from the cognitive search that I have configured. Why? Is there a setting missing in the code. Below is the sample code:

I am trying to choose the language to ASP.Net C# for the below code block, but it is only taking it as PowerShell. Sorry about that.

public async Task