If you are using an iPhone, iPad or Mac running iOS 11, and are experiencing problems with viewing rosters on your device, then this may be due to a new tracking prevention feature running on iOS 11.
If you disable this feature, you should be able to view rosters on your device.
To disable this tracking prevention feature please follow the below steps:
- Open the Settings app
- Scroll down to Safari and tap it
- Scroll down to "Prevent Cross-Site Tracking" and switch this off