mikrotik rb951 Samsung mobile problem

Hi
i recently created a captive portal redirecting users to my web page and after testing it with many smartphones i found problems with Samsung s6/s7 and iphones.
Users with Samsung phones after login open my webpage with chrome and immediatelly the page dissapears but still wifi is on.
Users with iphones after login they get a message ‘‘success’’ on the left top of the screen and cannot redirected to my web page.
Xiaomi, huawei,lenovo ,phones and tablets with old and new androids are ok.
My web page is http. not https
Any help?