Please answer these questions before submitting your issue.

Should this be an issue in the gRPC issue tracker?

Create new issues for bugs and feature requests. An issue needs to be actionable. General gRPC discussions and usage questions belong to:

• grpc.io mailing list
• StackOverflow, with grpc tag

Please don't double post your questions in more locations; we are monitoring both channels, and the time spent de-duplicating questions is better spent answering more user questions.

What version of gRPC and what language are you using?

1.6.0

What operating system (Linux, Windows, …) and version?

Linux

What runtime / compiler are you using (e.g. python version or version of gcc)

python3.4

What did you do?

If possible, provide a recipe for reproducing the error. Try being specific and include code snippets if helpful.
Run the hello world python grpc server and a python client

What did you expect to see?

Successful response from the server

What did you see instead?

2017-09-08 04:22:21,853 ERROR:Unable to connect to server
Traceback (most recent call last):
File "bazel-out/local-fastbuild/bin/server/tmp_pyc/server.py", line 414, in getValue
File "/usr/local/lib/python3.4/dist-packages/grpc/_channel.py", line 492, in call
return _end_unary_response_blocking(state, call, False, deadline)
File "/usr/local/lib/python3.4/dist-packages/grpc/_channel.py", line 440, in _end_unary_response_blocking
raise _Rendezvous(state, None, None, deadline)
grpc._channel._Rendezvous: <_Rendezvous of RPC that terminated with (StatusCode.UNAVAILABLE, Endpoint read failed)>

Make sure you include information that can help us debug (full error message, exception listing, stack trace, logs).
This exact same client and server work with 1.4.0

Anything else we should know about your project / environment?