You’ll need to go in via the CLI as they have removed this option from the GUI as of FortiOS v5.0, then enter the following commands to enable and configure system log messages to be exported to your BLËSK server.
config global config log syslogd setting set status enable set server [ip.or.dns-name.here] set port 513 end
To set the level of messages you want to see (optional).
config log syslogd filter set severity warning