I'm trying to make an embed command which will include the user in it, but every time I try and run it, I get an error about reading members, and I'm not sure how to fix it.

const Discord = require('discord.js')

module.exports = {
  name: 'giveaway',
  description: 'sends giveaway info',
execute(client, message, args) {
    const member = message.mentions.members.first() || message.guild.members.cache.get(args[0]);
    
    if(!args[0]) return message.channel.send('Please specify a user');
    
    if(!member) return message.channel.send('I can\'t seem to find this user.')
    
    const gaembed = new Discord.MessageEmbed()
    .setTitle('Congratulations', member)
    .setColor('GREEN')
    .setFooter('You have 24 hours from this message to claim your prize.')
    .setTimestamp()
    .setDescription('Congratulations! You have won a prize! Be sure to DM <@myuserid> to claim it, before it is rerolled.')
    message.channel.send(gaembed);
  },
};

This is the command handler in my index file:

client.on('message', message => {
        
    if (!message.content.startsWith(prefix) || message.author.bot) return;

    const args = message.content.slice(prefix.length).split(' ');
    const commandName = args.shift().toLowerCase();

    const command = client.commands.get(commandName)
        || client.commands.find(cmd => cmd.aliases && cmd.aliases.includes(commandName));
    
    if(!command) return;
    
    try {
        command.execute(message, args, client)
    } catch (error) {
        console.error(error);
        message.reply('There was an error trying to execute that command! Check the console for more details!');
    }
});