How to fix: PHP Fatal error: require(): Failed opening required 'autoload.php'

Introduction

You may find an error similar to the following in your website's PHP error log:

PHP Fatal error:  require(): Failed opening required 'autoload.php'

You may use the below procedure to attempt to resolve the issue.

Please keep in mind that the investigation, diagnoses, and resolution of PHP errors such as the one above are best handled by a developer or systems administrator with the skills, training, and expertise required to do so for you. Although this kind of issue is not caused by cPanel or the basic configuration of cPanel, we would like to offer the following guide as a courtesy.

Procedure

1. Login to the cPanel account for the user that owns the domain with the error

2. Click on the "Terminal" icon under the Advanced section. (Regular SSH access will work as well if you prefer.)

3. Use the cd command to change to the root of your site. Please consult with a systems administrator or developer if you do not know how to find the root of your site. This is different for every website.

4. Issue the following command to regenerate the autoload.php file.

composer update --no-scripts

If the above steps do not resolve your issue, you must contact a developer or systems administrator with the skills, training, and expertise required to resolve the issue for you. If you're not sure where to find a systems administrator, you can start here:

System Administration Services