Answers.Body: <p><code>Unknown error</code> messages in the control panel almost always happen over an AJAX request and are usually 500 response code Internal Server Errors, so there isn't an convenient way to display a meaningful error message with a full stack trace to help debug.  </p>
  
  <p>But you've found the next best thing... the error logs in <code>craft/storage/runtime/logs</code>.</p>
  
  <p>Usually if you see it on every page in the CP, it's from something like Craft trying to write a license file to the <code>craft/config</code> folder, but it can't. The error you shared is a 503 response, which means "Service Unavailable".  You'd typically only see that if a request comes into the front-end of the site while Craft is in the middle of an update, or the front-end of the site is offline.</p>
  
  <p>So I'm not 100% sure the error you posted is the one that's causing the "unknown error".  I'd enable <a href="http://buildwithcraft.com/docs/config-settings#devMode" rel="nofollow">devMode</a>, clear out all your log files, reproduce the problem and scour the logs again to see if anything else pops out.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-01-16T18:05:23.550Z
Answers.LastActivityDate: 2015-01-16T18:05:23.550Z
Answers.UserDisplayName: Brad Bell
Body: <p>How can I debug an 'Unknown error' message that I get with every request in Craft?
  Logging says:</p>
  
  <pre><code>******************************************************************************************************
  2015/01/16 14:03:36 [error] [exception.Craft\HttpException.503] exception 'Craft\HttpException' in /storage/www/imagecenter/acceptance/craft/app/etc/web/WebApp.php:873
  Stack trace:
  #0 /storage/www/imagecenter/acceptance/craft/app/etc/web/WebApp.php(218): Craft\WebApp-&gt;_processUpdateLogic()
  #1 /storage/www/imagecenter/acceptance/craft/app/framework/base/CApplication.php(180): Craft\WebApp-&gt;processRequest()
  #2 /storage/www/imagecenter/acceptance/craft/app/index.php(62): CApplication-&gt;run()
  #3 /storage/www/imagecenter/acceptance/htdocs/index.php(16): require_once('/storage/www/im...')
  #4 {main}
  REQUEST_URI=/index.php?p=admin/actions/users/getAuthTimeout&amp;dontExtendSession=1
  HTTP_REFERER=http://acceptance.imagecenter.blinkdev.nl/index.php?p=admin/entries
  ---
  2015/01/16 14:03:36 [error] [application]
  
  ******************************************************************************************************
  </code></pre>
  
Tags: <debugging>
Title: Best practices in debugging an 'Unknown error'
ThreadText: # Best practices in debugging an 'Unknown error'
  
  (Asked by: username_0 on 2015-01-16)
  
  How can I debug an 'Unknown error' message that I get with every request in Craft?
  Logging says:
  
  ```
  ******************************************************************************************************
  2015/01/16 14:03:36 [error] [exception.Craft\HttpException.503] exception 'Craft\HttpException' in /storage/www/imagecenter/acceptance/craft/app/etc/web/WebApp.php:873
  Stack trace:
  #0 /storage/www/imagecenter/acceptance/craft/app/etc/web/WebApp.php(218): Craft\WebApp->_processUpdateLogic()
  #1 /storage/www/imagecenter/acceptance/craft/app/framework/base/CApplication.php(180): Craft\WebApp->processRequest()
  #2 /storage/www/imagecenter/acceptance/craft/app/index.php(62): CApplication->run()
  #3 /storage/www/imagecenter/acceptance/htdocs/index.php(16): require_once('/storage/www/im...')
  #4 {main}
  REQUEST_URI=/index.php?p=admin/actions/users/getAuthTimeout&dontExtendSession=1
  HTTP_REFERER=http://acceptance.imagecenter.blinkdev.nl/index.php?p=admin/entries
  ---
  2015/01/16 14:03:36 [error] [application]
  
  ******************************************************************************************************
  
  ```
  
  **Tags:** debugging
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-01-16. Score: 2
  
  `Unknown error` messages in the control panel almost always happen over an AJAX request and are usually 500 response code Internal Server Errors, so there isn't an convenient way to display a meaningful error message with a full stack trace to help debug.
  
  But you've found the next best thing... the error logs in `craft/storage/runtime/logs`.
  
  Usually if you see it on every page in the CP, it's from something like Craft trying to write a license file to the `craft/config` folder, but it can't. The error you shared is a 503 response, which means "Service Unavailable". You'd typically only see that if a request comes into the front-end of the site while Craft is in the middle of an update, or the front-end of the site is offline.
  
  So I'm not 100% sure the error you posted is the one that's causing the "unknown error". I'd enable [devMode](http://buildwithcraft.com/docs/config-settings#devMode), clear out all your log files, reproduce the problem and scour the logs again to see if anything else pops out.
  
  
  ---
  
  