To modify the message or a web page when disabling a vhost BEFORE its installation it is here: edit this message at System Settings -> Server Templates -> Default settings -> Apache website, in the “Disabled website HTML” box. or Disabled website URL.
BUT,
How to modify the message or a web page when disabling a virtual server AFTER its installation please?
BEFORE you disable the vhost do:
In Virtualmin -> Server Settings -> Server Template :
Select the server template to disable
In Edit template section : select Apache website then in the block “Disabled website HTML” check “Entered below …”.
And write your custom message (ex : <h1><span style="color: blue;">SERVER IN MAINTENANCE</span></H1> )
Or put a web page with the “Disabled website URL” block…
Save.
Finally in Virtualmin -> Edit a server :
In the block “Configurable parameters” click on “Save and apply for the virtual server”.
The message will be customized after disabling the vhost!