title: an error "(error) ERR illegal address " happen in redis command
body: <pre><code>r-vy1ba7c1e3d09574.redis.rds.aliyuncs.com:6379&gt;
  r-vy1ba7c1e3d09574.redis.rds.aliyuncs.com:6379&gt;
  r-vy1ba7c1e3d09574.redis.rds.aliyuncs.com:6379&gt; auth asdkfjlasjdf
  (error) ERR illegal address
  r-vy1ba7c1e3d09574.redis.rds.aliyuncs.com:6379&gt;
  r-vy1ba7c1e3d09574.redis.rds.aliyuncs.com:6379&gt;
  </code></pre>
  
  <p>When I execute that command to verify, an error is caused.
  The password of auth is correct!
  I don't understand the meaning of the error.</p>