Here the Controller

Program.cs

Startup.cs
services.AddLocalization(opt => opt.ResourcesPath = "Resources");
var supportedCulture = new[]
{
new CultureInfo("en-US"),
new CultureInfo("fr-FR")
};
var requestLocalizationOptions = new RequestLocalizationOptions
{
DefaultRequestCulture = new RequestCulture("fr-FR"),
SupportedCultures = supportedCulture,
SupportedUICultures = supportedCulture
};
app.UseRequestLocalization(requestLocalizationOptions);
Seems it doesn't acess to resource , what do you think the problem is?