Error CS0120 in ASP.NET core?

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C#

ASP.NET5

I can't seem to get rid of this error
public void Configure(IApplicationBuilder app, IGreeter GetGreeting )
{
app.Run(async (context) =>
{

var greeting = Greeter.GetGreeting();

await context.Response.WriteAsync(greeting);
});
I've tried creating a separate instance of the class, but that creates other problems.

What I have tried:

I've tried creating a separate instance of the class, but that creates other problems because the Greeter class takes IConfigure as a parameter and a separate instance does not meet this requirement.