When a plate is not read, or not very well, a wrong camera position can be the problem, or the quality of the picture from the camera. Is the camera blinding by sunlight? Try to improve the WDR setting of the camera. Or the picture is too dark? Check if the time from the camera is OK because it regulates the day/night switch. Check also the time schedule that regulates the day/night behaviour, perhaps it stands on a summertime schedule and then the infrared lights are powered up to late in the evening. Is it already dark but the plates aren't light up? Check if the infrared light is on and again if the time is right. Is the glass in front of the camera-lens clean? Are plates sharp in the picture? If not try to adjust the lens. If needed check the camera manual, you can find it on the camera productpage.
It is possible that carl is working perfectly but your gate or barrier doesn't open. Probably there is a defect or safetydevice that is blocking the normal functioning of the gate. each time when Carl shows "Acces allowed" you can hear the relay on the IP or USB board "tick". If possible try to measure if the contact is made and if the contact is reaching the gate or barrier also.
For the most products we provide user manuals, software and tools. Practical tips you will find here, even with screenshots and videos Try to fix your problem first with this information. When you still have questions contact us.