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3

You could use this instead of commenting that out, which is from the NwebSec library:

app.UseXfo(options => options.SameOrigin());

You can also use a custom middleware to set the header, without the NwebSec package if that’s all it’s being used for!

app.Use(async (context, next) =>
    {
        context.Response.Headers.Add("X-Frame-Options", "SAMEORIGIN");
        await next();
    });