I have read a lot about it even here:
https://stackoverflow.com/questions/2271887/custom-error-page-for-http-error-503
Nothing worked for me.
When the application pool is stopped, it will always show the Service unavailable message from the IIS
The page I have is 503.html
what can be done to make it work?
Best Answer
https://docs.microsoft.com/en-us/iis/configuration/system.webserver/httperrors/error
The following HTTP errors can't be customized: 400, 403.9, 411, 414, 500, 500.11, 500.14, 500.15, 501, 503, and 505.