Couldn't reach server at '{}' to download vocabulary files.
Traceback (most recent call last):
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connection.py", line 157, in _new_conn
    (self._dns_host, self.port), self.timeout, **extra_kw
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/util/connection.py", line 84, in create_connection
    raise err
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/util/connection.py", line 74, in create_connection
    sock.connect(sa)
TimeoutError: [Errno 110] Connection timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connectionpool.py", line 672, in urlopen
    chunked=chunked,
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connectionpool.py", line 376, in _make_request
    self._validate_conn(conn)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connectionpool.py", line 994, in _validate_conn
    conn.connect()
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connection.py", line 334, in connect
    conn = self._new_conn()
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connection.py", line 169, in _new_conn
    self, "Failed to establish a new connection: %s" % e
urllib3.exceptions.NewConnectionError: <urllib3.connection.VerifiedHTTPSConnection object at 0x7f912c2cc550>: Failed to establish a new connection: [Errno 110] Connection timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/requests/adapters.py", line 449, in send
    timeout=timeout
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/connectionpool.py", line 720, in urlopen
    method, url, error=e, _pool=self, _stacktrace=sys.exc_info()[2]
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/urllib3/util/retry.py", line 436, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='s3.amazonaws.com', port=443): Max retries exceeded with url: /models.huggingface.co/bert/bert-base-chinese-vocab.txt (Caused by NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x7f912c2cc550>: Failed to establish a new connection: [Errno 110] Connection timed out',))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/transformers/tokenization_utils.py", line 360, in _from_pretrained
    resolved_vocab_files[file_id] = cached_path(file_path, cache_dir=cache_dir, force_download=force_download, proxies=proxies, resume_download=resume_download)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/transformers/file_utils.py", line 180, in cached_path
    resume_download=resume_download)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/transformers/file_utils.py", line 327, in get_from_cache
    http_get(url, temp_file, proxies=proxies, resume_size=resume_size)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/transformers/file_utils.py", line 243, in http_get
    response = requests.get(url, stream=True, proxies=proxies, headers=headers)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/requests/api.py", line 75, in get
    return request('get', url, params=params, **kwargs)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/requests/api.py", line 60, in request
    return session.request(method=method, url=url, **kwargs)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/requests/sessions.py", line 533, in request
    resp = self.send(prep, **send_kwargs)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/requests/sessions.py", line 646, in send
    r = adapter.send(request, **kwargs)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/requests/adapters.py", line 516, in send
    raise ConnectionError(e, request=request)
requests.exceptions.ConnectionError: HTTPSConnectionPool(host='s3.amazonaws.com', port=443): Max retries exceeded with url: /models.huggingface.co/bert/bert-base-chinese-vocab.txt (Caused by NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x7f912c2cc550>: Failed to establish a new connection: [Errno 110] Connection timed out',))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "bert.py", line 125, in <module>
    text_train, text_dev, text_test, label_train, label_dev, label_test = load_dataset('qa_dataset/Beauty_domain.txt', max_len = 60)
  File "bert.py", line 96, in load_dataset
    text_list = prepare_data(text_list)
  File "bert.py", line 54, in prepare_data
    tokenizer = BertTokenizer.from_pretrained("bert-base-chinese")
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/transformers/tokenization_utils.py", line 286, in from_pretrained
    return cls._from_pretrained(*inputs, **kwargs)
  File "/home/hgy/anaconda3/envs/pytorch-python3/lib/python3.6/site-packages/transformers/tokenization_utils.py", line 372, in _from_pretrained
    raise EnvironmentError(msg)
OSError: Couldn't reach server at '{}' to download vocabulary files.


Did you find out what the problem was @venusafroid ?<|||||>> Did you find out what the problem was @venusafroid ?

I think op had a problem connecting to s3 as shown in the log
```
requests.exceptions.ConnectionError: HTTPSConnectionPool(host='s3.amazonaws.com', port=443): Max retries exceeded with url: /models.huggingface.co/bert/bert-base-chinese-vocab.txt (Caused by NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x7f912c2cc550>: Failed to establish a new connection: [Errno 110] Connection timed out',))
```
@paulmwatson Not sure if it s the same issue for you. 
The cases for `EnvironmentError` varies. There are file not exist, archive format not recognized, and many other raise by OS.
I got cache directory access denied, for example.
You may refer to the earlier part of your log.

However, I think it is a bug having `"{}"` in log string. Maybe they forgot to put a more informative argument in the format string.