Samsung Galaxy S6 Edge: How to Block Unwanted and Unknown Calls in Android 5.1.1 Lollipop

When needed, you can set your Samsung Galaxy S6 Edge to automatically block calls come from a specific number or those you have not added to your contacts list by adding the phone number to the auto reject list and enabling the feature to reject calls from unknown numbers. But, you have to remember that this feature will only work to block calls from those with phone numbers, in other words, this feature can't be used to block private calls or calls come from those who hide their phone numbers.

How to block unwanted calls from a specific phone number?
You can do so by using the following steps:

1. Open Phone app.
2. Tap More at the top right and then select Settings.
3. Tap Call rejection.
4. Tap Auto reject list.
5. To manually add a phone number to the reject list, enter the required phone number you want to block. Alternatively, you can tap the Log button to pick up a phone number from your call logs, or tap the Contacts button to pick up a phone number from your contacts list.
6. Tap to add the entered phone number to the reject list.
7. To add more numbers to the reject list, repeat from the step #5.
8. From now on, incoming calls come from those you have added to the reject list will be blocked or rejected automatically.

How to block calls from unknown numbers?
You can do so by using the following steps:

1. Open Phone app.
2. Tap More at the top right and then select Settings.
3. Tap Call rejection.
4. Tap Auto reject list.
5. Slide the ON/OFF switch next to the Unknown option to the right enable this option. The switch turns green when this option is enabled.
6. From now on, incoming calls from unknown numbers(those you have not added to your contacts list) will be blocked or rejected automatically.

FYI, when a blocked phone number calls you, you will not get any notification (sound or vibration). However, your phone will keep recording all blocked calls in your call logs and flag them as rejected calls.