Resolution is low

Hello, I was using my unreal engine 4 normally up to an hour it started to crash and it appeared that my frame rate was low when View member was my game he was in low resolution, then I never got back normal resolution no way to fix this? be able to thank you!

Go to Settings → Engine Scalability Settings and set it to “Epic”. You may also want to uncheck “Monitor Editor Performance?” to prevent downgrading resolution.