Backpack.tf auto hides listings when it knows the inventory can't provide the proper items for a trade, and unfortunately someone else traded the metal just after it's last inventory refresh and before you could put in a trade.

<3

Why you doing buy order when you don`t have enough metal for pay?

This bot needs more pure

¡sell 1 Mann Co. Suply Create Key

😇

Approve the trade

Thanks Bogus, Apparently leaving a bot to do it's own thing for a week makes it fill up too much.

your backpack is full :)