title: session_start(): Failed to initialize storage module: memcache (path: /tmp) when enable memcache in yii2
body: <p>Today we enabled memcache on centos and every thing is ok. PhpMyAdmin also run well with memcache but when i tried to login with my application that developed by yii2 i got this error:</p>
  
  <pre><code>session_start(): Failed to initialize storage module: memcache (path: /tmp)
  </code></pre>
  
  <p>After this i tried to enable memcache in yii2 config file same as documentation.</p>
  
  <p>Here is my configuration in backend\config\main.php</p>
  
  <pre><code>'cache' =&gt; [
          'class' =&gt; 'yii\caching\MemCache',
          'servers' =&gt; [
              [
                  'host' =&gt; '127.0.0.1',
                  'port' =&gt; 11211,
                  'weight' =&gt; 60,
              ],
          ],
          'useMemcached' =&gt; true,
  
      ],
  </code></pre>
  
  <p>But after everything, problem not solved and i tired from searching web.</p>
  
  <p>In no forum and in no site no body don't talk why i face to this problem.</p>
  
  <p>Thanks for your help.
  This is so important because my admin page is crashed.  </p>