Discord.js mod机器人禁止命令不起作用

const Discord = require('discord.js');
const client = new Discord.Client();

client.once('ready', () => {
    console.log(`Logged in as ${client.user.tag}!`);
});

client.on('message', async message => {
    if (message.content.startsWith('!ban')) {
        const args = message.content.split(' ').slice(1);
        if (args.length < 1) {
            return message.reply('Please specify a user to ban.');
        }

        const user = message.mentions.users.first();
        if (!user) {
            return message.reply('User not found.');
        }

        const member = message.guild.member(user);
        if (!member) {
            return message.reply('User is not in this server.');
        }

        try {
            await member.ban();
            message.reply(`${user.tag} has been banned.`);
        } catch (error) {
            console.error(error);
            message.reply('I was unable to ban the user.');
        }
    }
});

client.login('YOUR_BOT_TOKEN');