App for IOS gets cripplingly slow responses from the net if more than one instance of the app is using the same internet connection. (differing user accounts)

Hi guys,

So I have and app that simply uses a couple coroutines to grab some values from the web. some are sore as html some as PHP or PHP mysql Queries.

In some points of the app the script will not allow the user to progress until the value has been received (I know I should do it in the background but in this instance i can't)

If I run the app on 10 devices so long as they are on different internet connections the app is super quick. it requests, gets the response, and moves on.

Problem is when I use a number of devices on the same internet connect (3 or even 2 in this case on a 50Mbps wifi router, a 100Mbps wifi router or tethered via and LTE device without the app running) one of the instances of the app will run quickly and the others will hang waiting for a response from the web server.

I fired over to stack overflow and asked if anyone knew of any limitations in PHP, MySQL or web servers in general that could be causing this and didn't really find out any answers. "Network issue" was the resounding consensus, Although I'm struggling to find what, I have tried this on many different setups with different ISPs, over 3G LTE and wifi and the same thing keeps happening.

Really could do with a steer and will be over the moon if I can get it solved here.

Thanks