Flask server crashes on EC2 t2.micro when called

I have ec2 t2.micro, there is flask on it with a classifier. I have also local script (python 3.6) that uses requests library to get classification response:

raw_elevation = [1,2,3,4, n , 100] # list of 100 integers

classifier_url = "http://xx.xx.xx.xxxx:1234/classify"

payload = {'Accept': 'application/json', 'Content-Type': 'application/json'}

profile_elevtion = {"data": str(raw_elevation)}

response = requests.post(classifier_url, params=payload, json=profile_elevtion)

It run 4 times and then flask crushed, local IDE throws this error:

Traceback (most recent call last):
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 600, in urlopen
    chunked=chunked)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 384, in _make_request
    six.raise_from(e, None)
  File "<string>", line 2, in raise_from
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 380, in _make_request
    httplib_response = conn.getresponse()
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\http\client.py", line 1346, in getresponse
    response.begin()
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\http\client.py", line 307, in begin
    version, status, reason = self._read_status()
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\http\client.py", line 276, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
http.client.RemoteDisconnected: Remote end closed connection without response
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\requests\adapters.py", line 449, in send
    timeout=timeout
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 638, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\util\retry.py", line 368, in increment
    raise six.reraise(type(error), error, _stacktrace)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\packages\six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 600, in urlopen
    chunked=chunked)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 384, in _make_request
    six.raise_from(e, None)
  File "<string>", line 2, in raise_from
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\urllib3\connectionpool.py", line 380, in _make_request
    httplib_response = conn.getresponse()
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\http\client.py", line 1346, in getresponse
    response.begin()
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\http\client.py", line 307, in begin
    version, status, reason = self._read_status()
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\http\client.py", line 276, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
urllib3.exceptions.ProtocolError: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',))
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "D:\PYTHON\directions\src\tools_set\utils.py", line 268, in classify_catch22
    response = requests.post(classifier_url, params=payload, json=profile_elevtion)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\requests\api.py", line 116, in post
    return request('post', url, data=data, json=json, **kwargs)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\requests\api.py", line 60, in request
    return session.request(method=method, url=url, **kwargs)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\requests\sessions.py", line 533, in request
    resp = self.send(prep, **send_kwargs)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\requests\sessions.py", line 646, in send
    r = adapter.send(request, **kwargs)
  File "C:\Users\user_X\Anaconda3\envs\dir2\lib\site-packages\requests\adapters.py", line 498, in send
    raise ConnectionError(err, request=request)
requests.exceptions.ConnectionError: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',))

What the hell is going on ? I do not even when to start debugging. Ec2 t2.micro is working fine.

What is weird, if if call the server with postman, no problems, but when I do it with pycharm... then it happens.