IP PIN

So just confused by the information being given and explained. So went to file my taxes for the first time in 3 years i think (i have not had to with my income not being enough to file) and everything went fine while filing with turbotax but then i get rejected for not providing my IP PIN which is a voluntary PIN given out by the IRS for people with cases of identity theft in the past.(from what i've read on the irs website and turbotax website) So why did i get rejected if its voluntary also if i need to have it to e-file my taxes, why isn't that stated? all it says its a PIN given out by the IRS and is voluntary so why cant i file without it? I've tried to retrieve it online but no luck because my license is invalid and cant get a state ID without it also i don't really get mail, like any so cant verify with that so what am i supposed to do?  also would love to know if its required to E-file then how is it a "voluntary" program?