If you want to deposit items to bandit.camp, you need to have SteamGuard AND the Steam Mobile Authenticator enabled for at least 14 days. Otherwise, your account cannot send trades.

Withdrawing items only requires you to have SteamGuard enabled.

You can find more info about this on Steam:

https://help.steampowered.com/en/faqs/view/6891-E071-C9D9-0134

In 2024, Steam updated their policy to impose a 2-6 hour trade ban on players who change their usernames. During this period, trading will be restricted, and we are unable to process trades with users who have an active trade ban. Once the ban expires, you will be able to trade again.

For more details, you can refer to this Reddit post describing the issue.

If you have recently changed your password, steam imposes a mandatory 10 day trade ban. After this has expired, you will be able to trade again