ipv4 not working on Android Marshmallow

[AC Question]

I observed something strange. When I test ipv4 and ipv6 connectivity on my iphone, they both work perfect. The Samsung galaxy tab S2 and Samsung galaxy S7 phone (both running Marshmallow) have no ipv4 connection. Only ipv6 works on them. I run the tests through the website www.ipv6-test.com