title: unable to start the jenkins service
body: <p>I'm very new to jenkins.
  I installed the jenkins by this:</p>
  
  <pre><code>brew install jenkins-lts
  </code></pre>
  
  <p>whiches was installed in the path of:</p>
  
  <pre><code>/usr/local/Cellar/jenkins-lts/2.204.1/libexec/jenkins.war
  </code></pre>
  
  <p>then I copied the <code>jenkins.war</code> into Download folder and run the command of <code>java -jar jenkins.war</code>.</p>
  
  <p>when I open the <a href="http://localhost:8080" rel="nofollow noreferrer">http://localhost:8080</a>, it always shows me the 503 error like this:</p>
  
  <pre><code>Request URL: http://localhost:8080/login?from=%2F
  Request Method: GET
  Status Code: 503 Service Unavailable
  Remote Address: [::1]:8080
  Referrer Policy: no-referrer-when-downgrade
  Cache-Control: no-cache,no-store,must-revalidate
  Content-Encoding: gzip
  Content-Length: 483
  Content-Type: text/html;charset=utf-8
  Date: Fri, 17 Jan 2020 13:20:33 GMT
  Expires: 0
  Server: Jetty(9.4.z-SNAPSHOT)
  X-Content-Type-Options: nosniff
  Accept: */*
  Accept-Encoding: gzip, deflate, br
  Accept-Language: en
  Cache-Control: no-cache
  Connection: keep-alive
  Cookie: Idea-9162083a=7af35695-da6a-4307-a39e-b0493b0245ba; JSESSIONID.b339e4d1=node06g9kw8xovnem1325lww2jfx880.node0; JSESSIONID.4f333b19=node0dvxpga8oouhul4beqym36aa90.node0; JSESSIONID.5d0d8859=node017xvlsusr2w881dxdwyfw8bhg00.node0
  Host: localhost:8080
  Pragma: no-cache
  Referer: http://localhost:8080/login?from=%2F
  Sec-Fetch-Mode: cors
  Sec-Fetch-Site: same-origin
  User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.117 Safari/537.36
  from: /
  </code></pre>
  
  <p>the log didn't show any errors.</p>
  
  <p>if I try to run the jenkins by brew, it shows me an error:</p>
  
  <pre><code>Error: Formula `jenkins` is not installed.
  </code></pre>
  
  <p>the java version is also the latest.</p>
  
  <pre><code>java version "1.8.0_111"
  Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
  Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)
  </code></pre>
  
  <p>where I did wrong? or should I config anything?</p>