How to display discord.js greeting message?

I got some problem when tried my discord.js bot to send a greeting when somebody come in the server. I followed all of the instruction from documentation, but it doesn’t change anything. My terminal didn’t send an error and any commands is useable. My discord.js version is 12.5.3

client.on('guildMemberAdd', member => {
    const lobbyChannel = member.guild.channels.find(ch => ch.name === 'lobby');
    if (!lobbyChannel) return;
    lobbyChannel.send(`Welcome to the server, ${member}`).catch(console.error);
});