TC I'm glad that your issue is resolved and thank you for posting your solution so that others experiencing the same thing can easily reference this!
Since the Microsoft Q&A community has a policy that the question author cannot accept their own answer, they can only accept answers by others, I'll repost your solution in case you'd like to Accept the answer.
Error Message:
In AI studio, I am creating a new chat playground out of the box and I can have a conversation with the model. Using the exact same deployment, I create an new Assistant Playground and get no answer from the model. How can I troubleshoot that situation?
Solution:
I was using an unsupported version of GPT. I updated the version and it now works.
To give more context, For Assistants you need a combination of a supported model, and a supported region. Certain tools and capabilities require the latest models. The following models are available in the Assistants API, SDK, Azure AI Studio and Azure OpenAI Studio. The following table is for pay-as-you-go. For information on Provisioned Throughput Unit (PTU) availability, see provisioned throughput. The listed models and regions can be used with both Assistants v1 and v2.
Please see Azure OpenAI Service models for more details.
If you have any other questions, please let me know. Thank you again for your time and patience throughout this issue.