When I copy paste it in my preferences, it shows nothing in the entry after it reloads. It says invalid URL if I try to anonymously purchase, though this may be because anonymous purchasing is disabled. I sent the link to a friend and myself and it works. I know that I can trade and can send trade offers. The only possibility I can think of is that as key icons are not showing up on outpost, they aren't being ID's correctly, but since you can still trade them, I don't see how this is a problem. Also, This shouldn't affect Trade URL being accepted.

Thanks for any and all help!

I saw that you have bought one game here, so I guess your problem is already resolved.
If not, you can try to renew your trade offer URL and try with the new one.