Event Streaming doesn't work

Hi all, I have forti300d and I've problem with one site "stooq.com". This site uses AutoQuote and on the left, chart and numbers should refresh themselfes but it doesn't work. When I connect with other network (for example at home) everything is OK. I added site to "trusted sites" using webfilter and created policy for common 80port (because this website uses event streaming at this port) but nothing has changed. What can I do to solve this problem?