The “minimizer’s name” is case sensitive (i.e., you must use “Minuit2”).
@Axel If “root-config --has-minuit2” returns “yes” but “Minuit2” is not working, then I think it is a bug (specific to the default ROOT installation on lxplus?).
BTW. The default minimizer (when the “minimizer’s name” is empty) is the old “Minuit”.