DFTB Parameterization

Matsci DFTBOptimization 

When i am trying to parameterize my molecules it is giving me errors on "No element pairs registered on  fitting"(attached).I have used Matsci for parameterization that have all the known compounds settings for my system .I even tried to use my own parameterization library that i got using DFTB on smaller fragment of molecules but got the same fitting error.Can you please tell me how can i proceed further.
Edu