I would power cycle the cameras for starters. After that you are trying to view the cameras via the ip address or the video monitoring software ? If the demo is working and not the admin password, i would defiantly make sure im not mistyping something. If you know you are not mistyping anything then you might have to reset the cameras to factory default.
You mentioned that you changed the password on the cameras so now If you are viewing the cameras though the monitoring software, you also have to go into the software to put in the NEW user name and passwords. This is under settings /cameras.
If you didn't change the setting in both cameras and software this could be causing a conflict
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