Today I checked on google developer tools under console tab and after I press Submit button it will show this error on console:
POST mywebsite.com/contact-us/ net::ERR_EMPTY_RESPONSE jquery.js?ver= 1.12.4:4
send @ jquery.js?ver=1.12.4:4
ajax @ jquery.js?ver=1.12.4:4
o @ jquery.form.mi.js?ver=3.51.0-2014.06.20:11
e.fn.ajaxSubmit @ jquery.form.mi.js?ver=3.51.0-2014.06.20:11
t @ jquery.form.mi.js?ver=3.51.0-2014.06.20:11
dispatch @ jquery.js?ver=1.12.4:3
r.handle @ jquery.js?ver=1.12.4:3
Do you have any idea?