If you found you can't repair your camera to your NVR, it will be that your camera's version not compatible with your NVR's. Pls kindly install a search tool to detect your camera's version and then upgrade it into the corresponding version. Then try to repair the camera to the NVR again.
1. Please connect the camera to the router by ethernet cable and power on the camera by an adapter.
2. Install this software on the computer to search the camera’s IP and its firmware version.
2.1). If the camera's version is lower than 1.7.8, pls upgrade it into 1.7.8 by the following steps(It need to upgrade it into 1.7.7 at first, then after its version is 1.7.7, then upgrade it into 1.7.8) After upgrade, pls note to reset the camera into factory setting.
Then after its version been 1.7.7, pls use the same method to upgrade it into 1.7.8
2.2). If the camera's version is between 1.7.8 to 1.9.3 (not including 1.7.8), pls upgrade it into 1.9.3 by the same method above. After upgrade, pls note to reset the camera into factory setting.
The 1.9.3 firmware:
You can also upgrade it into 2.3.1 version.
The 2.3.1 firmware:
Reset the camera after upgraded.