Langchain no longer works with OpenAI? All programs that worked correctly until a month ago no longer work. They all give me connection problems.

here a simple example. The Error it’s the same form any cide that use langchian.
The OpenAI API works fine from python.

from langchain_openai import ChatOpenAI
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.output_parsers import StrOutputParser

import myConfig

llm = ChatOpenAI(openai_api_key=myConfig.api_key)

prompt = ChatPromptTemplate.from_messages([
    ("system", "You are world class technical documentation writer."),
    ("user", "{input}")
])

chain = prompt | llm 
chain.invoke({"input": "how can langsmith help with testing?"})
output_parser = StrOutputParser()
chain = prompt | llm | output_parser
chain.invoke({"input": "how can langsmith help with testing?"})`

I get this error:

.......
  File "C:GenAI.venvLibsite-packageshttpcore_exceptions.py", line 14, in map_exceptions
    raise to_exc(exc) from exc
**httpcore.ConnectError: [WinError 10061] Impossibile stabilire la connessione. Rifiuto persistente del computer di destinazione
**
The above exception was the direct cause of the following exception:

........
  File "C:GenAI.venvLibsite-packagesopenai_base_client.py", line 1053, in _retry_request
    return self._request(
           ^^^^^^^^^^^^^^
  File "C:GenAI.venvLibsite-packagesopenai_base_client.py", line 986, in _request
    raise APIConnectionError(request=request) from err
**openai.APIConnectionError: Connection error**.

Any suggestion?