The most common reason for a callback notification to keep popping up is that you have leads with scheduled callbacks that are passed due. The system will notify you from time to time about these callbacks. If you wish remove these, you can either reschedule them or remove it's callback status.

This FAQ will guide you on how to do so

The system will remind the agent of pending callbacks by displaying a popup notification in the lower right side of the agent interface.

Click on the lead entry to open its lead info sheet.

 
In the lead info sheet, click the More tab in the upper part of the page and click on Redisposition to open the Redisposition window.

In the Redisposition window, click on the drop down option and select a different status other than the Callback status.

Once you selected a different Status, you can put a check mark on Modify Lead Status to override the previous call back status of the lead. Click on the Redisposition button to submit your selection.

Using the Snooze feature

The system will remind the agent for pending callbacks by displaying a notification in the lower right side of the agent interface.

2 - Click on the Snooze option in the bottom of the Pending Callbacks notification window to have the system notify you about these callbacks after 15 minutes.

You can also reschedule a callback. 

The system will remind the agent of any pending callbacks by displaying a popup notification in the lower right side of the agent interface.

Click on the Reschedule option in the right side of the Pending Callbacks notification window to open the Reschedule window.

Click the Callback's Time option to open the calendar window. To select a different month click the arrow button in the upper part of the calendar window. You may then select a day.

Once you select a day, the option will change to hour. You may now select what hour and if it’s in the morning AM box or afternoon PM box

After you select a specific hour, the option will change to minutes.

After selecting the minutes, your chosen callback time is now set and then click on Reschedule button.