For units with firmware manufactured after 2018, there is no backdoor. You must use the token system or physical reset.
The factory default password for many subscriber accounts is 1234 . napco dvr password reset new
Requires internal battery removal on some older models (not recommended for novices) Pros and Cons of the Reset Process FAQs - Napco Technical Library For units with firmware manufactured after 2018, there
If your DVR has a physical (often inside the case): napco dvr password reset new