Troubleshooting A "PHP Fatal error: Class not found" Error
Encountering an error similar to that shown below indicates a core WHMCS file is missing:
PHP Fatal error: Class 'xxxx' not found in /path/to/whmcs/vendor/whmcs/whmcs-foundation/lib/Exception/Handler/ExceptionLoggingTrait.php on line 0
Where xxxx is the name of a particular function.
To resolve this kind of error, read on:
Begin by downloading the Full Release Files corresponding to your WHMCS version from:
(If your licence is provided by a reseller, please contact them to obtain the files).
![](https://media.screensteps.com/image_assets/assets/000/574/194/original/7fb74000-9c4f-4fbd-b8d7-e55feb99bc0c.png)
Upload the .zip file to your server using your preferred method (FTP, File Manger etc.)
![](https://media.screensteps.com/image_assets/assets/000/574/198/original/a7e2d739-723c-4182-a8a8-1289af774f6c.png)
Extract the contents of the .zip file, overwriting the existing WHMCS files.
![](https://media.screensteps.com/image_assets/assets/000/574/196/original/8964ae39-2085-4575-a1f8-82e169fc2624.png)
Return to your WHMCS installation and the error should no longer occur.
The files could also be rendered inaccessible by inappropriate file/folder permissions or user/group assignment. Ensure that file and folder permissions are set correctly to allow all WHMCS files to be read by PHP. Please speak with your server admin/hosting provider to check the appropriate settings for your server environment.
If the error reoccurs a short time after re-uploading files, this indicates a server-side security measure is erroneously removing the file. Please speak with your server admin/hosting provider to adjust the security rule so as not to remove or quarantine the file.