"ERROR The license key is invalid.
ERROR The license is blocked. Provide a valid license key."
"Parallels Pro Control Panel was unable to contact the Parallels License
Server during the last attempt. Ensure that you are connected to the
network and that your firewall configuration is not blocking access to
the Parallels License Server."
CauseThe root of the issue is the lack of english locale in your system, requiered by Parallels Pro Control Panel.
# localedef -c -f UTF-8 -i en_US en_US.utf8
# export LANG=en_US.UTF-8
# /etc/rc.d/init.d/epld restart