I would suggest change the primary group of the user chris like this
usermod -g users chris usermod -g users chris This will change the primary group of chrischris from chris(1035)chris(1035) to users(100)users(100)
As I have no idea on how samba is configured, that is all I can suggest, you can always switch back to original config as follows.
usermod -g chris chris usermod -g chris chris Also ensure that user logs out and log in again after you make any changes in the groups.