We have a mobile data collector map that has a secure service (we use windows authentication), and after opening the map and entering my credentials it works great using Collector for iOS but it will not load the service in Collector for Android. The services just show up as grayed out and unable to turn on. I know that i'm entering my credentials correctly, as it accepts it (and testing using a wrong password it pops back up and makes me try again).
Again, this is the exact same mobile map and I'm using my exact same credentials, and it works in iOS but not Android. Is there some android security setting or something I am missing? I've tried it on a Samsung Galaxy Note Tab 12.2 running Android 5.1.1 as well a Samsung Galaxy Tab 4 running Android 4.4.2 and both give same results. It works great on an iPad running iOS 9.1.
iOS, layers available after entering secured credentials:

Android, unable to turn-on layers after entering secured credentials (only top two layers are secured, second layer is not). They are grayed out and unusable:
