title: PTY allocation request failed on channel 0
body: <p>I tried to ssh my router. It first shows:</p>
  
  <pre><code>@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
  @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
  @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
  IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
  Someone could be eavesdropping on you right now (man-in-the-middle attack)!
  It is also possible that a host key has just been changed.
  The fingerprint for the RSA key sent by the remote host is
  0e:82:bb:f1:3a:7f:1f:0d:3f:2d:26:dc:0d:81:61:6c.
  Please contact your system administrator.
  </code></pre>
  
  <p>Then I <code>ssh-keygen -R 192.168.0.1</code> (router IP). After that, I ssh again. However, after inputing the password, it shows:</p>
  
  <pre><code>PTY allocation request failed on channel 0
  shell request failed on channel 0
  </code></pre>
  
  <p>I tried several methods in stackoverflow, but fails. My router is TP-Link N750 with compiled openwrt firmware.</p>