Preferred Password not working in IPC-HDB4100EN-AS-0360B

[sydnew]

I m curious why I cant use my IP Camera preferred Password in my Hikvision OEM NVR even though it perfectly worked in IP camera browser and Blue Iris?. I m having a hard time trying to view my Dahua IP camera in NVR using my preferred password then I try admin/admin as username/password and it worked. all of my Dahua IP camera password worked perfectly fine with my preferred password only this particular Cam is not. did I miss something?