Plesk port 8447 can’t be opened

If you are having an issue while trying to upgrade Plesk (by opening port 8447) then there are something you need to check and clarify first. First, check if the server has a firewall. Second, check if server has low memory. Third, make sure port 8447 is allowed on iptables or firewall rules.

If those steps is not very solving, then you need to go to SSH first. As root.

[root@VPS ~]# ps aux | grep autoinstaller

Find the process ID (PID) and kill it.

[root@VPS ~]# kill -9 <pid>

After that restart psa service to spawn the installer again.

[root@VPS ~]# service psa restart

Try again to access Plesk on port 8447, see if opened.