I also experienced an issue with the Discord node.
I tried lots of things and even considered downgrading my version, but ultimately I think the N8N team has strict rules for validating the messages we send.
For me, it was the space between ‘ID’ and my ID; for you, I think it was the same. Downgrading your version is one solution, but I think the Discord node works properly. In my opinion, it was right.