hyperlink not opening in ads after scroll down

[pritich]

on our mobile site, m.123greetings.com , we have an ad at the bottom in floater position. After scrolling down, the bottom ads link stops working. again on scroll back to top of page , the bottom floaters ad link starts working. This happens only in the samsung s4 with the default browser, in all other devices and all other browsers it is working fine. please help urgently. cant imagine why this could be happening.