Bought 8 copies of Payday 2
Accepted trade offer but steam gave e 16 error.
Been doing this since then.
Bought other games but I guess they are stuck because of this now.
Seems like you need to reset something, thanks.

You should now have a trade offer of 4x Sniper Elite Nazi Zombie Army waiting for your accept.
The Payday 2 should come after this.