<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>

CC BY-SA 3.0
2015-01-16T18:05:23.550Z
2015-01-16T18:05:23.550Z
Brad Bell
<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>

<debugging>
Best practices in debugging an 'Unknown error'
# 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.


---

