What am I doing wrong, if this code works only when I specify the path to index.html in the URL? That is, it does not work: http: //Localhost: 3001 /API

So works: http: //LocalHost: 3001 /API /index.html -Documentation is displayed. Documentation is a Doc catalog with subcatalogues CSS, IMG, VENDOR, etc. + index.html, in which the relative path is registered to these subcatalogues.

So:= fiber.static {
        Index: "index.html",
        Compress: True,
        Maxage: 1,
        CacheDuration: 10 * Time.second,
    }
    Directory:= filepath.join (t.exe.dir, "../doc")
    App.Static ("/API", Directory, SO)

At the same time, a similar route for the root

SO= fiber.static {
        Index: "index.html",
        Compress: True,
        Maxage: 1,
        CacheDuration: 10 * Time.second,
    }
    Directory= FilePath.join (t.exe.dir, "../assets")
    App.Static ("/", Directory, SO)

works fine.