Azure-Cognitive-Search-Azure-OpenAI-Accelerator botframework test error

Question

https://github.com/MSUSAzureAccelerators/Azure-Cognitive-Search-Azure-OpenAI-Accelerator

I am testing my chatbot.
My code is based on above link.

I tested it by using Bot Framework Emulator and Post man

I turned on my local sever by using 'python app.py' and http://localhost:3978 is turned on.

Then I opened Bot Framework Emulater and I clicked 'Open Bot'

Bot URL : http://localhost:3978/api/messages

Microsoft App ID : My APP ID
Microsoft App password : My App client_secret

And I connected it.

I got that error.

And plus, I wanna test it through post man

POST
URL : http://localhost:3978/api/messages

Body : I followed bleow link and I wrote Body like Base URI example.

https://learn.microsoft.com/en-us/azure/bot-service/rest-api/bot-framework-rest-connector-api-reference?view=azure-bot-service-4.0

I wrote my bot 'Messaging endpoint' for 'serviceUrl' in Body

I think I wrote my body wrong. 'conversation', 'from' and something like that.

How can I fix it??? I wanna know some example for Body

Give me solution plz