adb cannot bind 'tcp:5037' : <p>It used to work fine, but today after I connected my Android phone to my machine, and run <code>adb devices</code>, I got the following error:</p>

<pre><code>* daemon not running. starting it now on port 5037 *
cannot bind 'tcp:5037': Address already in use
ADB server didn't ACK
* failed to start daemon *
error: cannot connect to daemon: Operation timed out
</code></pre>

<p>How to solve this problem? (I am using a MacBook)</p>
