The results are correct. If the transmission coefficient is zero, at the fermi level, it means that one of two things either there is no electrons with at fermi energy or either these electrons can not be transmitted the scattering region.
However in your case, we know from the density states calculation, that there is electrons at the fermi level, and therefore we know that it is due to this electron can not be transmitted through the scattering region.
So perfect analysis
