Unable to connect to the server via FTP:
ftp: connect: No route to host
nmap utility shows that port is filtered:
# nmap -p21 188.8.131.52
Starting Nmap 5.51 ( http://nmap.org ) at 2018-01-15 09:11 EST
Nmap scan report for 184.108.40.206
Host is up.
PORT STATE SERVICE 21/tcp filtered unknown
Access to the FTP is blocked by a firewall.
1. Make sure that there are no rules which prohibit FTP connection in Plesk in Tools & Settings > Firewall.
2. If the system or a third party firewall is active on the server, made sure that it is not blocking the connection to the required port.
3. There may be an intermediate firewall between. In this case, it is required to contact the service provider.