Connection closed without handshake response Error when using py2neo

[jaron1]

Hi there,

I am running a Neo4j Cloud VM instance of version: 3.4.12 (Enterprise).

I am facing an error when I attempt to connect to my Neo4j database via 'Bolt' protocol through py2neo v4.2 (I am building a web app that uses a Python-Flask backend server that connects with my Neo4j instance).

For example, to establish a connection, I run the following command:

from py2neo import Graph

Graph("bolt://mydomain.com:7687", auth=(NEO4J_USERNAME, NEO4J_PASSWORD), scheme='bolt', secure=True)

Do note that I have a custom domain attached to my server IP and I've followed the tutorial to set up an SSL certificate using LetsEncrypt following the guide at: https://medium.com/neo4j/getting-certificates-for-neo4j-with-letsencrypt-a8d05c415bbd

My Python Flask server is running locally at the moment, without an SSL cert.

The command results in the following error:

Traceback (most recent call last):
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "/venv/lib/python3.4/site-packages/flask_restful/__init__.py", line 269, in error_router
    return original_handler(e)
  File "/venv/lib/python3.4/site-packages/flask_cors/extension.py", line 161, in wrapped_function
    return cors_after_request(app.make_response(f(*args, **kwargs)))
  File "venv/lib/python3.4/site-packages/flask/app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/venv/lib/python3.4/site-packages/flask/_compat.py", line 34, in reraise
    raise value.with_traceback(tb)
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/venv/lib/python3.4/site-packages/flask_restful/__init__.py", line 269, in error_router
    return original_handler(e)
  File "/venv/lib/python3.4/site-packages/flask_cors/extension.py", line 161, in wrapped_function
    return cors_after_request(app.make_response(f(*args, **kwargs)))
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/venv/lib/python3.4/site-packages/flask/_compat.py", line 34, in reraise
    raise value.with_traceback(tb)
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/venv/lib/python3.4/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/venv/lib/python3.4/site-packages/flask_restful/__init__.py", line 458, in wrapper
    resp = resource(*args, **kwargs)
  File "/venv/lib/python3.4/site-packages/flask/views.py", line 88, in view
    return self.dispatch_request(*args, **kwargs)
  File "/venv/lib/python3.4/site-packages/flask_restful/__init__.py", line 573, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/venv/lib/python3.4/site-packages/flask_httpauth.py", line 104, in decorated
    return f(*args, **kwargs)
  File "/resources/base.py", line 20, in get
    data = graph.run(query).data()
  File "venv/lib/python3.4/site-packages/py2neo/database.py", line 526, in run
    return self.begin(autocommit=True).run(cypher, parameters, **kwparameters)
  File "/venv/lib/python3.4/site-packages/py2neo/database.py", line 805, in run
    entities=entities))
  File "/venv/lib/python3.4/site-packages/py2neo/internal/connectors.py", line 285, in run
    return self._run_1(statement, parameters, graph, keys, entities)
  File "/venv/lib/python3.4/site-packages/py2neo/internal/connectors.py", line 234, in _run_1
    cx = self.pool.acquire()
  File "/venv/lib/python3.4/site-packages/neobolt/direct.py", line 711, in acquire
    return self.acquire_direct(self.address)
  File "/venv/lib/python3.4/site-packages/neobolt/direct.py", line 604, in acquire_direct
    connection = self.connector(address, error_handler=self.connection_error_handler)
  File "/venv/lib/python3.4/site-packages/py2neo/internal/connectors.py", line 225, in connector
    return connect(address_, auth=cx_data["auth"], **kwargs)
  File "/venv/lib/python3.4/site-packages/neobolt/direct.py", line 967, in connect
    raise last_error
  File "/venv/lib/python3.4/site-packages/neobolt/direct.py", line 959, in connect
    connection = _handshake(s, resolved_address, der_encoded_server_certificate, **config)
  File "/venv/lib/python3.4/site-packages/neobolt/direct.py", line 905, in _handshake
    raise ServiceUnavailable("Connection to %r closed without handshake response" % (resolved_address,))
neobolt.exceptions.ServiceUnavailable: Connection to (*IP_ADDRESS*, 7687) closed without handshake response

In Chrome, I am able to use Neo4j Browser at "https://mydomain.com:7473" and log in successfully to "bolt://mydomain.com:7687".

To circumvent the problem, I run an HTTP connection and it works. For example:

from py2neo import Graph

Graph("http://mydomain.com:7474", auth=(NEO4J_USERNAME, NEO4J_PASSWORD))

Any help will be greatly appreciated! I would be happy to provide any necessary information.

Cheers!

[ashwanth467]

The issue still exists. Any update on this? I am stuck with this. Facing issue while establishing the connection to neo4j from docker container; while the same working properly outside.

[peterliu]

Same problem here... Can't find any solution on google...

[support1]

This is likely due to a mismatch in authentication. Whilst I didn't use this library, I did use the neo4j python driver and received the same issue. In our occurrence it was due to the python driver not using TLS whilst neo4j required it. We issued a new certificate to neo4j signed by a public CA, double checked DNS was setup correctly, connected the python driver over unencrypted bolt, and allowed this to occur with OPTIONAL setting within neo4j.conf file. We then used the prefix bolt+s to use encrypted traffic, tested, then forced neo4j to only accept TLS with REQUIRED within the neo4j.conf file.