It has been discovered that early shipments of this camera had a issue with the firmware that would cause the camera to lock out if the password was changed by the user when prompted. This has now been corrected by a firmware update 4.0.11.201710180946
http://www.vicon-security.com/software-downloads-library/vicon-camera-software
Once upgraded you will need to return the camera to factory defaults in order to be able to access the camera.
To do this you need to connect the Alarm1, Alarm2 and Alarm Ground together while the camera is on as shown in the picture below. The camera can then be rediscovered using the IPC Config tool.
V942D, V944D, V945D