Update vector-search-vectorizer-azure-open-ai.md

Updating with a limitation with AI Services and custom subdomain

Author: gmndrg

articles/search/vector-search-vectorizer-azure-open-ai.md

@@ -8,13 +8,17 @@ ms.service: azure-ai-search
 ms.custom:
   - build-2024
 ms.topic: reference
-ms.date: 08/05/2024
+ms.date: 10/16/2024
 ---
 
 # Azure OpenAI vectorizer
 
 The **Azure OpenAI** vectorizer connects to a deployed embedding model on your [Azure OpenAI](/azure/ai-services/openai/overview) resource to generate embeddings at query time. Your data is processed in the [Geo](https://azure.microsoft.com/explore/global-infrastructure/data-residency/) where your model is deployed. 
 
+Your Azure OpenAI Service must have an associated [custom subdomain](/ai-services/cognitive-services-custom-subdomains). If the service was created through the Azure portal, this subdomain is automatically generated as part of your service setup. Ensure that your service includes a custom subdomain before using it with the Azure AI Search integration.
+
+Note that Azure OpenAI models created with an AI Studio service account are not supported. Only models from the Azure OpenAI Service are compatible with this integration. 
+
 Vectorizers are used at query time, but specified in index definitions, and referenced on vector fields through a vector profile. The Azure OpenAI vectorizer is called `AzureOpenAIVectorizer` in the API. 
 
 + Use the [**2024-07-01**](/rest/api/searchservice/indexes/create) REST API or an Azure SDK package that's been updated to provide the feature.