I have two indicator variables, Female and Immigrant, which are omitted when I run a fixed effect regression. However, when I run the correlation between them, as well as between all of the variables in my model, there is nothing worth noting. There are no correlations between variables higher than .5 and most are under .1. So I'm asking myself, why are variables being omitted for collinearity?

Code:
xtset pid
xtreg logTurnoverIntention FBAny Satisfaction $Controls1, fe
gen SampleSize1 = e(sample)
xtreg logTurnoverIntention FBAny $Controls1, fe, if SampleSize1 ==1
xtreg Satisfaction FBAny $Controls1, fe, if SampleSize1 ==1