In certain scenarios, users encounter above message when they try to connect to their web hosting accounting using one of their ftp programs like filezilla, ws-ftp, cuteftp, smartftp
Solutions that seemed to have worked for me
i) Host name: Try adding ftp://www.mysite.com and set the port to 21
ii) User name: Try typing username@domain.com instead of just the user name of the ftp user
Tags: 530 login error, cuteftp, filezilla, ftp, smartftp, ws-ftp
This worked for me!