Receiving a "508 Resource Limit Is Reached" error when browsing a site on CloudLinux

Symptoms

The following error is displayed when visiting a website on a server using CloudLinux:

CONFIG_TEXT: 508 Resource Limit Is Reached 
The website is temporarily unable to service your request as it exceeded resource limit. Please try again later.

Cause

The "508 Resource Limit is Reached" error occurs when an account exceeds its assigned resource limit. On servers using CloudLinux, this typically occurs when an account exceeds LVE limits configured in WHM at Home / Server Configuration / CloudLinux Manager in the Users or Packages tabs.

Accounts can exceed resource limits for many different reasons. For example, a large volume of inbound or outbound site traffic, poorly optimized sites with increased inbound traffic and concurrent page requests, demanding backend operations - such as imports or exports, and webcrawlers making a high number of requests per second.

Resolution

You can fix this error by increasing the resources assigned to the account in WHM at Home / Server Configuration / CloudLinux Manager in the Users or Packages tabs or by reducing the amount of resources the account is using.

Additional Resources

How to adjust the CloudLinux LVE limits through WHM

How to view and edit CloudLinux limits by package

Why is my website very slow on CloudLinux?