https://docs.microsoft.com/ja-jp/iis/application-frameworks/running-classic-asp-applications-on-iis-7-and-iis-8/classic-asp-not-installed-by-default-on-iis
Classic ASP Not Installed by Default on IIS 7.0 and above

And Classic ASP is installed.

Thank you for res Marshall.

Sorry but what is mod_security?
How to disable rule #340162?

Hi, mod_security is a module used on Apache servers, do you know what type of server the site is on? Is your VPS self-managed or host managed what version of IIS is running on the server?

Winners never quit, quitters never win
CSS and Responsive Designs
User Manual for Ecommerce Templates

self-managed Windows Server 2012 R2 with IIS8.0

Hi as its a self-managed server we are limited on the help we can provided as it is out of the scope of the ecommerce software forum. You may have to look in your server logs as that may have a bit more information on the problem. I generally will browse to a page like cart.asp or search.asp then download the log for the day open in notepad using the find feature in notepad search for the page you just browsed to cart.asp or search.asp and check the entry for that page as it hopefully will have more information on the problem.

Winners never quit, quitters never win
CSS and Responsive Designs
User Manual for Ecommerce Templates

I'll do so and back here if I find some.
Thanks for help!