Steam servers are probably messed up, try again later.

https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/0/558747922562007365/

Ask in your appeal.

https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/0/558747922562007365/

https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/0/558747922562007365/

The only thing you can is report the user.

To report him to Outpost refer to the link below.
https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/0/558747922562007365/

Use this link to report them to SteamRep.
http://steamrep.com

This really isn't the place to argue about this and starting a useless flame war about who is at fault doesn't help either. We can't do anything for you in this case as it is not in the general publics hands. You reported him. The conversation can be done.

With the odds stacked against you like they currently are. Just forget it and buy an Unusual for a decent price with the extra keys you have. You will be much more satisfied atleast having one rather than not.

Clear your cache, you don't need to change your DNS server.

As Blue Screen stated. If a trade is old and inactive, it can and should be reported. But Outpost will check the users' activity on site before taking any action. Some people simply don't reply in their own trades, therefore one should not assume the user is inactive based on that only.

We cannot view your Outpost tickets either, maybe give a link to the trade(s) so we can see what you were reporting.