my iphone cannot connect to an unsecured public network

This is a public wifi in a hospital. I go through the effort of connecting using the iphone Settings | Wi-Fi page. then Safari pops up asking for a confirmation, which I give. everything then seems to be OK but in seconds, I get a No Internet connection flag on the wifi entry field.

this same network works well on my PC. After some queries, I noticed that it works on android phones but not iphones in general. Is there some sort of setting on iphones that is preventing access?