- Plesk for Linux
- SSH access is not available from some of IPs
- Such IPs are not listed as banned in Plesk > Tools&Settings > IP Address Banning (Fail2Ban) > Banned IP Addresses
- Plesk Firewall is disabled Plesk > Tools&Settings > Firewall
Most likely, ISP or hosting provider firewall blocks the connection.
Contact ISP or hosting provider support to open SSH port.