Invalid subscription ID, does not have access to Agents

> Please provide us with the following information:
> ---------------------------------------------------------------

### This issue is for a: (mark with an `x`)
```
- [x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
>

### Any log messages given by the failure
> File "E:\Python\Python313\Lib\site-packages\azure\core\pipeline\policies\_universal.py", line 615, in deserialize_from_text
raise DecodeError(
...<3 lines>...
) from err
azure.core.exceptions.DecodeError: JSON is invalid: Expecting value: line 1 column 1 (char 0)
Content: Exception Type: BadRequestException
Message: Invalid subscription ID, does not have access to Agents.
Stack Trace: at Microsoft.MachineLearning.Rag.EntryPoints.Transforms.ProjectProxyTransform.b__18_0(RequestTransformContext transformContext) in /mnt/vss/_work/1/s/src/azureml-api/src/RAG/EntryPoints/Transforms/ProjectProxyTransform.cs:line 128

### Expected/desired behavior
>

### OS and Version?
> Windows10

### Versions
> 22H2 (OS build 19045.5131)

### Mention any other details that might be useful

> ---------------------------------------------------------------
> Thanks! We'll be in touch soon.

Start by reproducing the reported failure in the Azure Agent Runtime sample using the provided Windows and Python versions, then inspect the Azure SDK deserialization path at azure/core/pipeline/policies/_universal.py:615. Compare the response with the ProjectProxyTransform.cs line 128 stack trace; done means identifying why the subscription is rejected or documenting the required access configuration.

Written by the indexing model from the issue text.