When configuring video cameras for use with the Flexreader™ plugin, set the maximum gain to prevent high noise levels in the images and to prevent overexposure of the license plates in the images.
Opposite to what you would expect, overexposure of license plates is more common in darkness. In dark environments, the camera uses its maximum allowable gain and shutter time. With these settings, license plate characters might not be visible, as shown in the following image.
When this occurs, reduce the maximum gain of the camera. You can usually find settings to limit the gain in the camera setup page accessible through a web browser connected to the IP camera.