Link Failover not working Properly in pfsense 2.3.2

[psramacharyulu]

We have two WANs (wan1 & wan2). we created link failover gateways.
if wan1 down then it goes to wan2. but only https websites are working and
http websites are not opening..
what is the reason for above problem...

Sir,

We have two ISP for pfsense firewal
ISP1 is down
on ISP2
the internet working but youtue, google search,yahoo search, wiki search are working
and
if type www.yahoo.com the page was not loading
but if type https://www.yahoo.com the page was loading
every url working in https://xxxxxxxx.xxx

what was problem please guide me