why my board settings reset it’s supposed to be brown, but it is green? and why I cannot changeback
Go to https://www.chess.com/settings/board
After setting the board to whatever you want, scroll down and click save.
hmmm, go to https://www.chess.com/play/online
then click setting and change board to Dark wood or walnut then click SAVE.... : )
On the website:

If you're on the iOS app, it's a known issue and I believe should be fixed in a future version update.
Are you on the iOS app? I know at least one board color is missing and being worked on.
my board is this weird green color no matter what i put in the settings , and the peices look naf as well