show con dyn=ntp
You need to nominate an existing NTP server as a peer server to obtain the current time from. You also need to set your offset from Coordinated Universal Time,(CUT or GMT)
Assuming you are using 193.133.123.129 as your time server, the following set of commands should work.
add ntp peer=193.133.123.129
set ntp UTCOFFSET=0:00
enable ntp
If ntp has been previously configured, disable and delete the peer before trying to reconfigure.