Lavan Mahes Greetings & Welcome to Microsoft Q&A forum!
Make sure that you're assigned at least the Cognitive Services Contributor role for the Azure OpenAI resource.
The following table summarizes the RBAC role assignments needed for all Azure resources associated with your application.
For more details, see Role-based access control for Azure OpenAI Service and Assign Azure roles using the Azure portal.
Do let me know if that helps or have any further queries.