This error usually occurs because a firewall on your server is blocking connections from the website builder on the port your FTP service is running on (usually port 21). Allow connections from Site.pro's IPs on your server on your FTP port, port 80, and any ports you've configured for passive FTP connections.If you're using an on-premises builder installation, also allow the IP address of your on-premises builder installation server. cPanel If your server uses ConfigServer Security & Firewall (CSF), the most common firewall on cPanel servers: Log in to WHM.Search for and open "ConfigServer Security & Firewall" under Plugins.Find the "csf - Quick Actions" section (or the "Firewall Allow IPs" tab).Enter the IP address in the "Quick Allow" field and click "Quick Allow". This adds the IP to the csf.allow file. If your server uses a different firewall (e.g. plain iptables), whitelist the IP through that tool instead. Plesk Log in to Plesk.Go to "Tools & Settings".If Plesk Firewall is enabled, open it and add the IP to the allow rules.If Fail2Ban is enabled, go to "IP Address Banning (Fail2Ban)" > "Trusted IP Addresses" and add the IP there as well, so it doesn't get temporarily blocked after failed login attempts. DirectAdmin If your server uses ConfigServer Security & Firewall (CSF), the most common firewall on DirectAdmin servers: Log in to DirectAdmin with an admin account.Open "Additional Features" and click "ConfigServer Security and Firewall".Under "Quick actions", enter the IP address and add it to the whitelist. This updates the csf.allow file. DirectAdmin's own black/white lists only control access to the DirectAdmin web interface, not FTP or other services, so make sure the IP is whitelisted at the firewall level (CSF or iptables), not just in DirectAdmin's own lists. Note: the exact steps can vary depending on the firewall service installed on your server.