If all done correctly, then one of the reasons is that you didn't have enough funds.
Every follower does the same trade as a Trader.
Wunderbit USDT normally has trades of only 10% of the portfolio (not too risky). For example, you have 100 USDT, then only 10 USDT on your account will be used for the trade. Some strategies use only 4%, so again, if you have 100 USDT, your account will use only 4 USDT for the trade.
HOWEVER, Binance minimum requirement is 10 USDT for a trade. So, your order will be failed. Best solution is to have more funds on the account. Wunderbit Futures (another trading account available in Marketplace) on FTX normally takes 100% of the funds for a trade, so it makes more sense if you have less than ~300 USD on your account.
in the copy-trading tab (upper menu), do you see that you follow the trader?
Are you sure that open positions of a trader were open after you started following him?
Do you see any new trades coming in on the dashboard? If yes, but they are failed, click on it to see details.