CRITICAL - Plugin timed out after 55 seconds


Hi everybody,

I am a new to Nagios so I can’t deal with a problem.
I have Nagios installed on a box with wrong date. After I change date, Nagios goes crazy showing messages like the one in the subject for all the hosts that reside in my network, although they are OK.
I supose it takes some time for Nagios to synchronize, but it lasts too long, it’s already 2 hours.
How can I solve this in a short time manner?