REX Server IP Addresses
Some servers require you to whitelist IP addresses to allow an FTP connection to happen. Some of these blocking systems like BitNinja.io display a screen to you when you attempt to connect via FTP like this one.
The issue is that the REX server cannot press these buttons so you will need to provide the following FTP addresses to them to add to the whitelist.
REX Server IP Addresses to whitelist with your hosting provider are:
BitNinja Security Notice Screen.