Yes, I can get
ftp://main.aminet.net with the Internet Explorer, too. And that's indeed 35.223.124.178, but when I try the same with Filezilla, I get "Access denied" now, never had that before. Maybe I get blocked again, the same happens with my email ...
Solved: Sorry, the new version of Filezilla was still blocked in my firewall. Now the connection was possible and the upload of the latest IconLib successful.