URGENT! All of our AI Foundry Models using the Responses API stopped working!

Hallo Microsoft Team,

as of today all of our API using the Azure Responses API stopped working, no matter the selected model!

from None\nopenai.InternalServerError: Error code: 500 - {'error': {'message': 'The server had an error while processing your request. Sorry about that!', 'type': 'server_error', 'param': None, 'code': None}}"}

We tested this code from the playground:

from openai import OpenAI

endpoint = "https://XYZ.openai.azure.com/openai/v1"
deployment_name = "gpt-4o"
api_key = "KEY"

client = OpenAI(
    base_url=endpoint,
    api_key=api_key
)

completion = client.chat.completions.create(
    model=deployment_name,
    messages=[
        {
            "role": "user",
            "content": "What is the capital of France?",
        }
    ],
)

print(completion.choices[0].message)

And it seems to work:

python testapi.py 
ChatCompletionMessage(content='The capital of France is **Paris**.', refusal=None, role='assistant', annotations=[], audio=None, function_call=None, tool_calls=None)

But when trying the Responses API:

import os
from openai import AzureOpenAI

endpoint = "https://XYZ.openai.azure.com/"
deployment_name = "gpt-4o"
api_key = "KEY"

client = AzureOpenAI(
    azure_endpoint=endpoint,
    api_key=api_key,
    api_version="2025-04-01-preview",
)

resp = client.responses.create(
    model=deployment_name,
    input="What is the capital of France?",
)

print(resp.output_text)

We get:

.venv/lib/python3.12/site-packages/openai/_base_client.py", line 1047, in request
    raise self._make_status_error_from_response(err.response) from None
openai.InternalServerError: Error code: 500 - {'error': {'message': 'The server had an error while processing your request. Sorry about that!', 'type': 'server_error', 'param': None, 'code': None}}

Everything worked great yesterday afternoon, so it does not seem to us as if we broke something on our part.

Please, we need immediate help since all of our AI applications stopped working.

Thank you in advance.