Assistant API création d'un thread en kotlin - pas de réponse à la requête http

API
1

la requête de création du thread renvoie le code 200 mais aucune donnée n’est renvoyée! Impossible d’obtenir le ThreadId. Pourquoi.
Ci-dessous le code en Kotlin:
val createdAssistantResponse = createAssistant(apiKey, org_ID, assistant)
val assistantId = JSONObject(createdAssistantResponse).getString(“id”)

                     val jsonBody = """
				{
 				   "messages": [{
     			   "role": "user",
    			    "content": "Hello, what is AI?"
   				 }, {
      		  	  "role": "user",
     			   "content": "How does AI work? Explain it in simple terms."
 				   }]
			 }
			""".trimIndent()

                     val mediaType = "application/json; charset=utf-8".toMediaType()
                     val requestBody = jsonBody.toRequestBody(mediaType)
                     val request = Request.Builder()
                         .url("https://api.openai.com/v1/threads")
                         .addHeader("Authorization", "Bearer $apiKey")
                         .addHeader("OpenAI-Beta", "assistants=v1")
                         .addHeader("Content-Type", "application/json")
                         .post(requestBody)
                         .build()
                     val response = withContext(Dispatchers.IO) {
                        client.newCall(request).execute()
                     }
                     val threadId = JSONObject(response).getString("id")