Quoting from ntpd documentation:
In case there is no TOY chip or for some reason its time is more than
1000s from the server time, ntpd assumes something must be terribly
wrong and the only reliable action is for the operator to intervene
and set the clock by hand.
Again, quoting from the ntpd man page:
-s Set the time immediately at startup if the local clock is off by more than 180 seconds. Allows for a large time correction, eliminating the need to run rdate(8) before starting.
So a ntpd -s in a terminal should be sufficient to fix the problem and let ntpd adjust the time normally from there on.
UPDATE: now it should be ntpd -g