How to remove red lines

[BenTam]

I copy and simplify the following code from a Microsoft webpage. However the word "Coffee" is redlined. Anyway to remove the red lines?

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace AsyncBreakfast
{
class Program
{
static async Task Main(string[] args)
{
Coffee cup = PourCoffee();
}

private static Coffee PourCoffee()
{
Console.WriteLine("Pouring coffee");
return new Coffee();
}
}
}

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