Bem onde está sendo declarada:
string resposta = chat.GetResponseFromChatbotAsync().GetAwaiter().GetResult();
Está tendo o seguinte erro assim que compila:
System.Net.Http.HttpRequestException: 'Error at chat/completions (https://api.openai.com/v1/chat/completions) with HTTP status code: TooManyRequests. Content: {
"error": {
"message": "You exceeded your current quota, please check your plan and billing details. For more information on this error, read the docs: https://platform.openai.com/docs/guides/error-codes/api-errors.",
"type": "insufficient_quota",
"param": null,
"code": "insufficient_quota"
}
}