I use FileZilla for FTP. When I try to do my periodic backup of my public_html folder, it starts chomping away just fine then times out and locks me out of my site (completely - cannot view on web, log into cPanel, connect on FTP, nothing) for about 5 minutes.
I know that it is a simple setting in the FTP program like active vs passive, a port setting (using port 21, as directed by host) or limiting the # of connections, all of which I have tried, and to no avail. I recall that I was able to correct this issue before but I can't recall what I did, and I have since switched PCs so I lost my settings, and I've tried many recommendations that I found googling the issue. Still locks me out.