If you don't know the UID of your camera, please refer to: How to Find UID of Reolink Products
For example: Launch Reolink App on your phone, then tap on icon to enter the Device Settings page. (Even if the device can not be connected, you can find the UID.)
Cause 1: Upgrade the wrong firmware(or too old firmware) for the camera.
Please upgrade the firmware to the latest version. The firmware files are categorized by different hardware versions in the firmware center:
Please go to Firmware Center and find the correct firmware.
If you’re not sure about it, please share the system info page with the support team and we will help you identify. Please refer to: How to Find out System Information (Firmware Version) via Reolink Software
Cause 2. Incorrect UID and settings.
Cause 3. The UDP ports are blocked by the network firewalls.
Solution: Refer to use NTP to synchronize time to check whether you can sync the time succeeded. If you can, it means that that UDP ports are opened. If not, please check the NTP settings and your local network settings to ensure that UDP ports are not blocked by the firewalls.
Note: If you are on some special networks (hospital/hotel/school/office), please try to contact the IT admin for some help.
Cause 4. Your device is blocked by the system firewall of the login terminal.
Note: If you fail to log into your device via UID on Reolink App, please switch to another network (switch to 4G or another Wi-Fi) and try it again.