using filezilla to ftp with the default settings will cause the server firewall to assume you are a hacker and block you for 15 minutes. This is because filezilla tends to upload/download  many files at the same time. You can upload 50,000 files one by one if you like, but not all at one time. Actually the best method would be to zip the folder in zip format and then on cpanel=>file manager unzip the folder, this way you upload everything in short time and you sure nothing is missing.

Another solution is to use a ftp software which 100% compatible with our servers and that is coreftp, which is free, and you can download it at:

Please be sure to select ftp and port 21.

But going back to the filezilla, by changing the settings you can still use it to ftp:

in that window modify the following parameters, to have all the same value:
Maximum Simultaneous Transfers: 2
Limit for concurrent Downloads: 2
Limit for Concurrent Uploads: 2
or modify the value until you found one that is ok for you. In my case 3 is the optimum with my Internet connection and with our servers.

In case yo get blocked please don’t hesitate to contact support with your IP so we can unblock you.