So I'm creating a third-party to discord verification bot, and all of it works, except for when I try to access the guild member. The third-party sends all the data back to the bot, but for some reason, (and all the information is correct), it doesn't allow me to get the guild member, (via their discord id), and change their nickname.

Here's the code, and any help is appreciated!

let Mem = message.guild.members.cache.find(Member => Member.id === String(message.content.split(' ')[0]));

Mem.setNickname(message.content.split(' ')[1]);

I've tried (what I think) is all of the ways to access the guild member, but none of them work. The id is valid, which is why it's even more confusing. Thanks in advance!