Hi Guys,
Found the problem, it’s not with the server or theme.
For some reason, I use the same theme, same plugin settings and etc on wordpress 3.5.2, the contact form works like a charm.
This time the front end and back end able to respond and return with a test email.
On 3.6 and above, the contact form doesn’t work and return with a blank display.
What could cause the conflict?