most apps don't recognise my network connection - but one or two do!

I have an iPhone 6, iPad air 2 and an iPad mini 2 all with iOS 8.4.1. All were fine for the first couple of weeks after upgrade but then I came over to the US to work for a few weeks and the first week I'm here my iPad air started having a WiFi problem. I tried a list of stuff to fix it unsuccessfully but wasn't overly worried as my iPad mini did still work. Then this week my iPad mini started having exactly the same issues. So far (fingers crossed as I write this) my iPhone is okay.

So the issues is that I connect to WiFi in a hotel or airbnb rental and it says it has connected - asks for a password if it needs one and all seems fine initially. Most of the apps don't recognise that I'm connected - although weirdly Chrome and Facebook do recognise the connection so the WiFi is working and its something on the iPads that isn't telling the apps its there? I haven't tested every single app but the only ones I've found that work so far are Facebook and Chrome - anything with an apple ID required don't work and email doesn't work amongst others. The issue is consistent even when I moved from one apartment to a hotel then to another apartment all in different states and obviously different routers.

I've tried the following:

• forget this network - and then rejoin
• reset all network settings
• hard reset the iPad (holding the home and power buttons down for 10+ seconds)
• from a Google search also set http proxy to auto
• from a Google search also set DNS to 8.8.8.8

What I can't do:

• reset the router - most often it isn't available to reset - hotel, rental house or apartment, etc...
• reset the iPad with iTunes - my iTunes is on my Mac several thousand miles away for the next few weeks

Has anyone got ideas how to fix this without access to the routers or my iTunes setup? I've only been here in the US for less than 2 weeks and have another 6 weeks ahead of me which isn't appealing without a working iPad.

thanks