It is not possible to access the server via FTP.
Trying to check connection to 21 port locally, the error occurs:
C:\>telnet 203.0.113.2 21
Connecting To 203.0.113.2...Could not open connection to the host, on port 21: Connect failed
FTP service is running:
Firewall allows connections to FTP ports.
FTP sites are missing in IIS at IIS > Sites.
IP addresses are present in Plesk > Tools & Settings > IP Addresses.
There is no FTP site in IIS, so FTP service does not listen to the 21 port on 203.0.113.2 IP address. The site is missing because there are no domains on the required IP address.
Plesk configures FTP site in IIS automatically when there is at least one subscription with Web Hosting is created with the IP address.
Create a subscription in Plesk with the 203.0.113.2 IP address.