Android Update

Lock screen has turned orange/red

While I was overseas and NOT using my Samsung J2 as a phone (flight mode turned ON) I noticed that the lock screen had turned an orange red color AND I was receiving an error message that my storage was severely LOW and to free up space. I removed unnecessary ‘clutter’ from BOTH the internal storage AND external (CD card) storage and the error went away HOWEVER the lock screen remains a red/orange color (instead of the default green color – I don’t have a ‘wallpaper’?) I have searched the internet and youtube and cannot find a reason.
Can anyone ‘point’ me in the correct ‘direction’ to fix this.

Today 04:43 PM