I am encountering challenges in configuring Varnish cache on a separate server from the one hosting my WordPress sites through Plesk. The primary goal is to optimize website performance by efficiently implementing Varnish cache. Despite my initial efforts, I have encountered difficulties in establishing a connection between Varnish and my WordPress websites. The issues seem to be rooted in configuration gaps, resulting in multiple errors during the setup process. To overcome these challenges and successfully deploy Varnish, I am seeking a detailed, step-by-step guide. This guide should comprehensively address each stage of the setup, from initial configuration to troubleshooting, with a specific focus on resolving the issues preventing the proper connection between Varnish and my websites. Some of the errors I have encountered include the failure to establish a connection between Varnish and my website. Additionally, I have identified deficiencies in the configuration that need to be addressed for the optimal functioning of the Varnish cache. I appreciate your assistance in providing a comprehensive guide that will enable me to troubleshoot and deploy Varnish effectively in my Plesk-hosted environment, ensuring seamless integration with my WordPress sites.