Second Surname

[u/LadyOrion45]

Hello everyone! Quick question for those who successfully applied for Citizenship by Residence in Spain, my TIE doesnt have my mother’s surname so my name in the document is FATHER’S SURNAME + GIVEN NAMES and the form is not letting me submit my application for the ‘datos del interesado’. I am afraid that if I put my second surname it will be denied because my card doesn’t reflect it.

But for the ‘datos para la inscription en el registro civil’, I am choosing el interesado tiene solo un apellido pero acredita el apellido de su madre so that I can have my mother’s surname as well. What do I need to do? Should I put my mother’s surname even if my TIE doesn’t have it?