This error occurs when more than three concurrent FTP connections are attempted on the same login.
This can be because more than three people are connected to your site through a single FTP account, which can happen if you have a team working on the site, or it can be because your FTP client is attempting to make multiple connections to increase transfer speed.
In your FTP client, there should be an option to set the number of simultaneous connections. If to set this to a maximum of three, this should eliminate the problem.
Also ensure that no other computers are connected to the server at the time when you connect.
Article ID: 301
Created On: Fri, Mar 13, 2015 at 3:33 PM
Last Updated On: Thu, Apr 23, 2015 at 12:39 PM
Online URL: https://www.heartinternet.uk/support/article/why-do-i-get-error-530-maximum-number-of-users-when-connecting-to-my-site-through-ftp.html