What does it mean if AuthenticationMethod has AllowedAuthentications set as null?

[masters3d]

I have a server where I am sending password, and keyboard-interactive authentication methods. The password fails so it uses keyboard interactive.

Right after I connect I am getting the sshclient.ConnectionInfo so I can log some data.

// ConnectionInfo looks like this in ssh.net but I am interested in Authentication Methods

class ConnectionInfo {
....
public IList<AuthenticationMethod> AuthenticationMethods { get; }
...
}

This is the code that does the printing:

                // Log information about the connection authentication methods
                foreach (var eachAthenticationMethod in connectionInfo?.AuthenticationMethods ?? new List<AuthenticationMethod>())
                {
                    Log($" Strategy: {eachAthenticationMethod?.Name},  AllowedAuthentication:  {string.Join(",", eachAthenticationMethod?.AllowedAuthentications ?? (new List<string>()).ToArray())}");
                }

This is what I am printing.

Strategy: password, AllowedAuthentication: publickey,password,keyboard-interactive
Strategy: keyboard-interactive, AllowedAuthentication:

keyboard-interactive's AllowedAuthentication is null.

What does it mean if AuthenticationMethod has AllowedAuthentications set as null?