Opmanager 9 > URL Monitor : Host Unavailable

Opmanager 9 > URL Monitor : Host Unavailable

Hi Everyone,
 
I have a problem about URL monitor. I added URL WebSharePoint (intranet) for monitor ULR Web Site  but i found the error : The URL http://xxxx.co.th is Down, Reason : Host Unavailable .
 
and i tried search on ManageEngine Community but solution can't work for me.
 
please kindly suggest methods for solve this problem.
 
Regards,
Aehbudjet 
 
 
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