Answers.Body: <p>Is this shared (managed) hosting, or a VPS? First thing to check is that you have not run out of disc space.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-09-04T09:54:15.673Z
Answers.LastActivityDate: 2024-09-04T09:54:15.673Z
Answers.UserDisplayName: Seth Warburton
Body: <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>
  
Tags: <yii>
Title: Fatal Yii error out of the blue
ThreadText: # 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
  
  
  ---
  
  ## 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.
  
  
  ---
  
  