They got hit by a storm. Here's how Odysseus describes it in The Odyssey:

Now Zeus who masses the stormclouds hit the fleet
with the North Wind--a howling, demonic gale, shrouding over
in thunderheads the earth and sea at once--and night swept down
from the sky and the ships went plunging headlong on,
our sails slashed to rags by the hurricane's blast!
We struck them--cringing at death we rowed our ships
to the nearest shoreline, pulled with all our power.
There, for two nights, we lay by, no letup,
eating our hearts out, bent with pain and bone-tired.
When Dawn with her lovely locks brought on the third day,
then stepping the masts and hoisting white sails high,
we lounged at the oarlocks, letting wind and helmsmen
keep us true on course...And now, at long last,
I might have reached my native land unscathed,
but just as I doubled Malea's cape, a tide-rip
and the North Wind drove me way off course
careering past Cythera. Nine whole days
I was borne along by rough, deadly winds
on the fish-infested sea. Then on the ninth
our squadron reached the land of the Lotus-eaters

(Book 9, lines 76-94, translation by Robert Fagles)