rss problems

-- HikaShop version -- : 2.6.3
-- Joomla version -- : 3.4.5
-- PHP version -- : 5.5
-- Error-message(debug-mod must be tuned on) -- : none

hi

im tyring to use rss feed to display my products to other websites.

i tried to add www.mysite/product-lising?format=feed

on joomla 3.7 = displaying but no images
joomla 2.5 = Error loading feed data.
joomla 1.5 = Error loading feed data.

can you please guide me

thank you