On your AndroidLollipop smartphone many data is synchronized when the device is connected via Wi-Fi or mobile data connection to the Internet. This includes, for example, synchronizing e-mails, contacts, WhatsApp messages, your Samsung account and many more.
Now it may be that all of a sudden your Android Lollipop smartphone does not properly synchronize these data. If that's the case, then please check if you has disabled in Android Lollipop the master sync. This can be checked as follows:
The Master Synchronization in Android Lollipop can be easily activated as follows, so that all accounts receive the synchronization again.
Pulls with two fingers the status bar from the top to the middle of the screen. So you see all the quick selection fields of the Android Lollipop system. One of them reads: "SYNC"
This is the master synchronization in Android Lollipop. Tap on this, so that it is marked as green and thus becomes active.
You have now successfully reactivated the Master synchronization for your Android Lollipop smartphone. All apps that need to be synchronized, should again function properly.