Stuck on captive.apple.com when connecting to Walmart wifi

Why can't I connect to the wifi at any Walmart? Everyone I speak to who has an iPhone with ios9.4 or later cannot load the captive.apple.com. It stays on a white screen saying it'll be redirected automatically but never does. I have an iPhone 4s with iOS9.2 and it takes me to the captive page where I agree to the terms and Im connected. It was the same with my iPhone 5s before I did the update. It's every Walmart I've been to and only iPhones will not connect. It's only Walmart wifi with the issue. Any other public network works fine. Does anybody know the fix to this?