yzFhtxLFRAzgiFIBKUTROwmSXXT was the name passed into it, it doesn't use real names because that would take too much effort for nothing.

Look at the actual, and figure out what your code is doing wrong.

Throw just causes an exception to appear, for an example

throw new NotImplementedException("Greet is not implemented.");

will send an exception of NotImplementedException with the description "Greet is not implemented"

You can always ask for help on #csharp channel of Codewars Discord. Someone there will definitely be willing to explain.

(Offtopic answer deleted)

While it's not necessary to complete the kata, I have no idea as to what 'throw' and therefore 'throw new' does. I feel like I have reasonable knowledge of try catch structures but 'throw' has always evaded me. I've looked online but all the explanations tend to be vague or beyond my understanding. Could someone please help me out with this?