I'm not receiving chat room notifications.

It's same as Lysn chatroom alert. 
Press ‘Chat notification settings’ on More Options(…) - ‘Settings’ on the upper right side of the screen.
You may set up message arrival notification settings, contents to be displayed on the screen and whether to show pop-up notifications on lock screen or not.

※ How to turn off notifications for a certain chat room  
After entering the chat room you want to change notification settings, press More options (︙) button.
You may press the bell-shaped icon on the upper right side to turn on/off the notification of the applicable chat room.