How can I get two random strings from two arrays in C#

how can I get two strings from two arrays randomly. I have something, but It doesn't pick randomly.

string[] firstNames = { "John", "Michael", "Victor", "Mark", "Alex", "Steven", "Zack", "Howard", "Xzavier", "Brendan", "Dustin", "Carl" };
string[] lastNames = { "Adams", "McGregor", "Piasta", "Semmel", "Laris", "Sever", "Bourque", "Percy", "Shanabarger", "Bobak", "Adair" };
string[] shuffled = firstNames.OrderBy(n => Guid.NewGuid()).ToArray();
string[] shuffled2 = firstNames.OrderBy(n => Guid.NewGuid()).ToArray();
Random firstn = new Random();
Random lastn = new Random();
int index = firstn.Next(firstNames.Length);
int index2 = lastn.Next(lastNames.Length);
Console.WriteLine($"The random name is {firstNames[index]}" + $" {lastNames[index2]}");

I am trying to make a random full name generator. I have tried this code multiple times and the results were: John Adams, Victor Piasta, and so on! And as you can see they are not random.