WWW http request loads way to long on IOS

Hello
I am facing a big problem lately that i try to fix for 3 days now (its very urgent). I can't really tell where it could come from, so i explain it as detailed as possible. The main thing is, that something works on Android but without any reasons not on IOS

First step: Please watch this video (it's a screenrecording):
https://youtu.be/xbAa-QbjjVc

The information are loaded with www and http like that:

 string URL = "http://URL TO SERVER";
 WWW w = new WWW (URL); 
 yield return w; 

Round Screen:

(I know. I will use the gameObject.getComponent() func after i fixed that bug.)
The player data gets loaded in the "void Update()" in RoundScreen and in the "void update()" in setGenderProfilePics. "setQuestion" generates an ID and sends it to server via http to set the question for the "Question Screen"

Question Screen: here the question gets loaded and attached to the text.

Unity Version: 2017.4.1f1
XCode Version: 10.0
Macbook: 10.14 (Mojave)

How can i fix this issue? Thank you for your help!!