"Invalid security code format" error message?

[PPeter]

After accessing my DS-7608NI-M2/8P without issues earlier, it started reporting user/password incorrect.
Using 'Forgot password/email verification' I obtained a reset code from HikVision. But when I used it it reports 'invalid security code format,' so briefly that I missed it during several attempts to use the code.
Has anyone come across this? Any ideas on how to proceed? Rebooting the box doesn't help.
Thanks

 

[PPeter]

I used SADP to obtain another code and that worked