Why doesn't SSI work in Apache?

Question

Apache HTTP Server

Good day!
There is a task to insert the contents of one HTML file into another HTML file.
The easiest way in my opinion is to insert via SSI, but for some reason it does not work.
There is a file in the root directory - file.shtml I include
in the index.html file;
<!--#include virtual="Путь до файла/file.shtml"-->
And nothing happens. There are no errors in Apache.
There is an Options +Includes directive in the config.
Where to dig?

Answer 1

There is such an option on the client side (javascript): includeHTML
About SSI: httpd.apache.org/docs/current/mod/mod_include.html
(mod_include apache module - included?!)