I have a new virtual server configured as per "The Perfect Server - Ubuntu 18.04" running ISPconfig 3.1 and all updates to the system are done and monitor state is showing green across the board: State: ok (0 unknown, 0 info, 0 warning, 0 critical, 0 error) I am migrating a number of websites from an older physical server running Centos and ISPConfig3.0.5 but that is somewhat irrelevant except to note that DNS has the majority of the domains still pointing to this older server including www/mail for client#2 The first client migrated without any issues so client#1 website, ftp and email is working perfectly using Lets Encrypt SSL . The second website is causing me a real headache and I just cannot see what is wrong. Client#2 is a large ecommerce website so I wanted to set up a temporary URL to test it on the new server prior to switching over DNS to point to it. I set up a subdomain for client#2 and published dns entry which directs to the new server's IP address , this client is also using Lets Encrypt SSL. However, when I type the subdomain into a browser it is serving up the webpage and ssl certificate for client#1 instead. Any ideas why Apache might be serving up the wrong website ? Could there be corruption somewhere? I have tried a number of methods for creating temporary URLs using 'Website auto alias' at the server level and 'Alias domain for the website' so wondering if something has corrupted a config file somewhere ?