<p>Is this shared (managed) hosting, or a VPS? First thing to check is that you have not run out of disc space.</p>

CC BY-SA 4.0
2024-09-04T09:54:15.673Z
2024-09-04T09:54:15.673Z
Seth Warburton
<p>A site running an older version of Craft has all of a sudden stopped loading and instead, returns this error on every page (including the admin panel):</p>
<pre><code>Fatal error: Uncaught Error: Class &quot;yii\web\HeaderCollection&quot; not found in 
/home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php:322 Stack trace: #0 
/home/maiarellistudio/vendor/yiisoft/yii2/web/HtmlResponseFormatter.php(37): 
yii\web\Response-&gt;getHeaders() #1 
/home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php(1070):
yii\web\HtmlResponseFormatter-&gt;format(Object(craft\web\Response)) #2 
/home/maiarellistudio/vendor/craftcms/cms/src/web/Response.php(271): 
yii\web\Response-&gt;prepare() #3 
/home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php(337): 
craft\web\Response-&gt;prepare() #4
home/maiarellistudio/vendor/yiisoft/yii2/web/ErrorHandler.php(136): 
yii\web\Response-&gt;send() #5 
home/maiarellistudio/vendor/craftcms/cms/src/web/ErrorHandler.php(138): 
yii\web\ErrorHandler-&gt;renderException(Object(yii\base\ErrorException)) #6
/home/maiarellistudio/vendor/yiisoft/yii2/base/ErrorHandler.php(288):
craft\web\ErrorHandler-&gt;renderException(Object(yii\base\ErrorException)) #7
[internal function]: yii\base\ErrorHandler-&gt;handleFatalError() #8 {main} thrown in /home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php on line 322
</code></pre>
<p>I don't even know where to being troubleshooting. Any advice?</p>
<p>Thanks</p>

<yii>
Fatal Yii error out of the blue
# Fatal Yii error out of the blue

(Asked by: username_0 on 2024-09-03)

A site running an older version of Craft has all of a sudden stopped loading and instead, returns this error on every page (including the admin panel):
Fatal error: Uncaught Error: Class "yii\web\HeaderCollection" not found in 
/home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php:322 Stack trace: #0 
/home/maiarellistudio/vendor/yiisoft/yii2/web/HtmlResponseFormatter.php(37): 
yii\web\Response->getHeaders() #1 
/home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php(1070):
yii\web\HtmlResponseFormatter->format(Object(craft\web\Response)) #2 
/home/maiarellistudio/vendor/craftcms/cms/src/web/Response.php(271): 
yii\web\Response->prepare() #3 
/home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php(337): 
craft\web\Response->prepare() #4
home/maiarellistudio/vendor/yiisoft/yii2/web/ErrorHandler.php(136): 
yii\web\Response->send() #5 
home/maiarellistudio/vendor/craftcms/cms/src/web/ErrorHandler.php(138): 
yii\web\ErrorHandler->renderException(Object(yii\base\ErrorException)) #6
/home/maiarellistudio/vendor/yiisoft/yii2/base/ErrorHandler.php(288):
craft\web\ErrorHandler->renderException(Object(yii\base\ErrorException)) #7
[internal function]: yii\base\ErrorHandler->handleFatalError() #8 {main} thrown in /home/maiarellistudio/vendor/yiisoft/yii2/web/Response.php on line 322

I don't even know where to being troubleshooting. Any advice?
Thanks

**Tags:** yii

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## 1 answers

### Answer by username_1 on 2024-09-04. Score: 1

Is this shared (managed) hosting, or a VPS? First thing to check is that you have not run out of disc space.


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