How to mock a method so whenever called it returns same result in NSubstitute

Question

I am using NSubstitute nuget package for mocking in my .NET 6 testing project.

I am mocking a method return like this :

var resulttttt = authService.GetToken().Returns(mockedResult);

Then I create an instance of required service

var tokenService = _injection.ServiceProvider.GetRequiredService<ITokenService>();

This call internally calls GetToken which we mocked earlier, but it does not return mockedResult instead it again makes a call

var result = await tokenService.ValidateToken(token); 

How can I force it to returned mocked result whenever called.