We require Steam Guard (via email or mobile authenticator) to be enabled for 15 days to help protect your items and Steam Wallet funds from being misused by someone who may have illicitly obtained your password. If you have not had Steam Guard enabled for 15 days, you will be unable to trade or use the Community Market. Accounts that currently have Steam Guard disabled will be unable to trade and use the Community Market.

引用自 L：

Hello, I want to ask if there is a solution to overcome the 15 days trade hold on Steam. I've activated Steam Guard Mobile but there's still a trade hold of 15 days.