Steam might be having some connection issues with your backpack, try opening and closing TF2 (or close it if you already have it open) and check your Steamcommunity backpack.
If the items still do not show up then the trade might not have gone through, you will have to check your trade history and verify that the trade went through.
Items disappear in-game when they are used in a trade offer. This is enforced by Valve to prevent item-duping exploits, if the trade offer failed to go through, the items will be returned after a map change or you disconnect from the server you are on. We have no influence on this behavior.
If the bots gave you the wrong amount for your item, don't panic. Post in the refunds section and make sure to read the guidelines!
This means you may have taken too long to accept the trade offer. Offers have a limit in our bots before they are automaticly canceled. There may also have been an error or you were kicked due to maintenance.
Make sure that your metal and items are tradable and craftable. If you aren't able to see the metal via the Steam Community backpack, then you will have to wait a few minutes or close TF2 so your it gets updated.
If you are experiencing this error while trying to pay with items, it most likely means that we are not accepting said item for whatever reason or that it is overstocked.
There are different reasons why you might be experiencing this:
Before trading again make sure that:
This might happen when we are experiencing issues with the steam api, making all tradeoffer urls seem faulty to us. Otherwise it might be because you have done something which triggered SteamGuard's protection. Things like changing your email, changing your password, logging in from a new device or browser, logging in from a browser after clearing your cache and cookies, changing your authenticator device, and other things of the sort trigger so.
You will have to wait up to two weeks in order to be able to trade again, you can find more information regarding this topic in the following Steam Support article https://support.steampowered.com/kb_article.php?ref=1047-edfm-2932
Related : scrap.tf/help/kb/170
As the message says, you might have a trade ban or your inventory might be set to private. Make sure that your inventory settings are set to public and that you haven't done anything which could trigger SteamGuard's protection. Things like changing your email, changing your password, logging in from a new device or browser, logging in from a browser after clearing your cache and cookies and things of the sort trigger such protection.
If it's because SteamGuard, you won't be able to trade for a week.
Make sure that
That's because of an issue on Steam's end (most of the times), making our bots unable to check if the trade will end getting put in hold or something similar.
The only way to fix this issue is to keep trying until the trade goes through or wait some minutes and try again. Sometimes it might take you a lot of tries because of the Steam issues that were stated before.
This is a common issue that you might experience a lot due to some Steam issues and other reasons.
Steam has a feature which basically allows anyone to report an account for trade-scams. If enough people do this, the account will be automatically flagged. This process is completely automatic and no human will review these reports, so it's being abused by users who don't like us.