I turned on Chatroom notifications, but no notification comes in. (Android)

To receive app notifications normally, you need to grant permission to exclude the app from battery optimization. 
Please check the settings in the path below:

---

1. If the battery optimization pop-up appears when running the app, 
please exclude the app from battery optimization. 
※ If you have already excluded the app from battery optimization, the pop-up will not appear.

2. If the pop-up does not appear, 
go to Apps > More > Settings > Notifications and set it as follows:
1) Exclude the App from Battery Optimization 
Please exclude the app from battery optimization. 
※ If it is already excluded, the option will not appear. 
※ This applies to Android 6.0 or higher and app version 1.2.11 or higher. 

2) Turn On Background Data 
Please give the app permission to use background data. 
※ If it is already permitted, the relevant option will not appear. 
※ This applies to Android 7.0 or higher and app version 1.2.11 or higher. 

The latest version of the application is required to change notification settings, so download the latest version from an app store.
[App Download Links] 
▶ Android: https://bit.ly/2RzesBM
▶ iOS: https://apple.co/2F9HnpN