Why is members undefined?

Im trying to make a discord bot that detects when a specifi user joins a voice chanel but i ran into this error code and dont know what to do about it.

It says that members is undefined, why?

const client = new Discord.Client({ intents: ['Guilds', 'GuildMessages', 'MessageContent'] });

const Guild = client.guilds.cache.get("942493418419028059"); 
const Member = Guild.members.cache.get("623916311029743617"); 

if (Member.voice.channel) { 
    console.log(`${Member.user.tag} is connected to ${Member.voice.channel.name}!`);
} else {
    // The member is not connected to a voice channel.
    console.log(`${Member.user.tag} is not connected.`);
};