BR500 and cannot reset new password after seting router back to default settings

I have tried numerous times to reset the password from default to an new password and it will not validate and I connot change any settings as its keeps telling me to change password.

went thought manual ad did manual settings serveral times< put in admin the password and it tells me to reset the password and I put password in the fist line as old password the try and put a new password and then confim the new pas word and get invalidated 

i cannot updat the firmware also.

Jerry,