A. The problem may occur when the network environment is unstable

     or the OS version doesn’t meet the minimum specifications.

     It may occur also when there is not enough space in your device memory(RAM).

   Please try the step below at the stable network environment.

■  How to get additional device memory

: Clear data and cache in installed Apps in your device.

- Tap on [Settings] > [Apps and Notifications] > Tap on installed Apps > [Clear Cache] > [Clear Data]

※  The steps may vary device to device.

■  Delete not using Apps and information.

 - Delete useless data like currently not using Apps, photos and videos.