Please perform the following steps to resolve the issue:
1- Launch the Settings app, tap on Display → Edge screen → Edge lighting, and then tap the switch to activate it.
2- Click on Manage notifications and tap on the switches next to apps to receive notifications as the edge lighting. Note: Some notifications may not display as the edge lighting depending on notification types.
For further assistance, register your concern in Samsung members app (Open Samsung members app>click on “+“icon>send feedback> Error report/Ask Questions).