The problem with support of 21:9 smartphone on Android (game package)

Hello,
after I package my game and launch the game on the 21:9 smartphone, the game does not cover the screen (grey stripes from the both sides). I tried to change the resolution by the console command and in-game settings, change aspect ratio of the camera etc. I also tried to check the current screen resolution by the blueprint called “get supported fullscreen resolution” but the package on the android cannot check that values.

I am sure that it is not a problem with the phone settings because when I installed the game called PUBG mobile the resolution was properly 21:9 as it should be. Please help me to solve this problem :(. My current engine version: 4.27.

Problem solved.

https://forums.unrealengine.com/t/full-screen-mode-does-not-work-for-me-on-my-phone/481432/2