title: Git responds with 'error in sideband demultiplexer'
body: <p>I have two servers set up (as far as I know) exactly the same. On one of them, committing with git has always been fine, however on the second one, I've started getting this error:</p>
  
  <blockquote>
    <p>fatal: The remote end hung up unexpectedly<br>
    error: error in sideband demultiplexer</p>
  </blockquote>
  
  <p>Everything is the same between the two, including the contents of the <code>.git/hooks/post-receive</code> file.</p>
  
  <p>Is there a step in configuration I've missed somewhere, or something? I've tried reinitialising the repo twice now, to no avail.</p>
  
  <p>My post-receive file is as follows:</p>
  
  <blockquote>
    <p>#!/bin/sh<br>
    cd ..<br>
    env -i git reset --hard</p>
  </blockquote>