Can´t connect 6S to some public wifi hotspot that requires authentication

I can´t connect my iphone 6S into some public hotspots that requires password authentication. Curiously I get an apple.com page instead of the hotspot authentication page. I do can connect my company´s 5S at same time and same hotspot without any problem. I did the Reset Network Setttings of the 6S, but did not resolve the problem.