title: Xdebug Could not connect to debugging client. Tried: localhost:9000
body: <p>I used before Xdebug v2, but after last update I faced with Xdebug v3.0.0, I replaced all what needed by the update user <a href="https://xdebug.org/docs/upgrade_guide#changed" rel="noreferrer">guide</a></p>
  <p>I'm using Docker.</p>
  <p>my debug conf</p>
  <pre><code>#xdebug.remote_enable=true
  xdebug.mode=debug
  
  #xdebug.remote_port=9000
  xdebug.client_port=9000
  
  xdebug.remote_host=172.17.0.1
  
  xdebug.remote_handler=dbgp
  
  #xdebug.remote_autostart=1
  xdebug.start_with_request=yes
  
  #xdebug.remote_connect_back=0
  xdebug.discover_client_host=0
  
  xdebug.idekey=PHPSTORM
  xdebug.show_error_trace = 1
  xdebug.max_nesting_level=250
  xdebug.var_display_max_depth=10
  #xdebug.remote_mode=req
  
  xdebug.remote_log=/var/log/r_xdebug.log
  xdebug.log=/var/log/xdebug.log
  </code></pre>
  <p>and what I get in log when try to execute any PHP script :</p>
  <pre><code>tail -f /var/log/xdebug.log
  [888] Log opened at 2020-11-29 10:39:51.670762
  [888] [Step Debug] INFO: Connecting to configured address/port: localhost:9000.
  [888] [Step Debug] WARN: Creating socket for 'localhost:9000', poll success, but error: Operation now in progress (29).
  [888] [Step Debug] WARN: Creating socket for 'localhost:9000', connect: Cannot assign requested address.
  [888] [Step Debug] ERR: Could not connect to debugging client. Tried: localhost:9000 (through xdebug.client_host/xdebug.client_port) :-(
  [888] Log closed at 2020-11-29 10:39:57.515970
  </code></pre>
  <p>When I try to execute the URL in a browser PhpStorm does not start debugger, but I checked</p>
  <pre><code>lsof -i :9000 | grep LISTEN
  </code></pre>
  <p>listen port appeared when I click listening in PhpStorm.
  My conf was sync <code>File | Settings | Languages &amp; Frameworks | PHP | Debug</code> -&gt; Debug port 9000</p>
  <p>What's wrong with my Xdebug config and what I need to do?</p>