His account is blocked from having new copiers due to reaching the maximum AUM (Assets Under Management) for his tier. That means the problem is on their side and there's nothing you can do about it. This is usually a temporary block so they'll need to monitor or change their risk level before can eToro lift this restriction. It usually takes a month or more so just try checking it again after a month or so. In case that account is still blocked from getting copied by that time, I suggest that you consider exploring other traders. There are plenty of other interesting eToro users who have good portfolios.
