Our template do not switch as smartphone for samsung galaxy s4

Dear,

We used the mobile joomla for the mobile site. but we have the blank screen for the smartphone galaxy s4 and other tab whr\ere we switch the tab display mode to mobile.

if(!$MobileJoomla_Device['markup'])                $MobileJoomla_Device['markup']  =       'xhtml';


in side file
/home/wapportal/telecel_portal/plugins/system/mobilebot.php

What is URL of your website? Do you have MJ-related errors or warnings in error_log file?