Equifax lets identity thieves raid "frozen" credit reports through its shady, obscure secondary credit bureau

"Freezing your credit report has no effect on NCTUE; what's more, NCTUE operates in a careless and incompetent fashion, with invalid SSL certificates and other glaring errors. NCTUE has a separate system for freezing your credit report there, but it doesn't work -- filling in the form and submitting it just returns obscure errors. You may be able to freeze your report by calling NCTUE, but they might charge you a separate fee, and there's no guarantee you'll get through."

https://krebsonsecurity.com/2018/05/another-credit-freeze-target-nctue-com/