The Hikvision Reconnecting.Error Code HCNetSDK.dll[91] occurs on the iVMS-4200 software and it’s an indication that there’s not enough power juice for the camera or that the Auto-change stream type is enabled.
The fastest solution to solve this issue is to use a better PoE switch and turn the auto-change stream type off. In this guide, you can find steps on how to fix this reconnecting error code issue.
How to fix Hikvision reconnecting error code 91
1. Not enough power
This is most likely the main cause of this issue. The camera is not getting enough power juice, it’s struggling and it’s going on and off.
When using a PoE switch to power up the camera, you need to make sure that the switch is certified to be used with PoE cameras and that it follows international standards. So, just make sure you’re using the correct PoE switch.
2. Turn off the auto change stream
The Hikvision IP camera or recorder (DVR NVR) uses two types of video stream: main stream and sub-stream.
These types of streams depend on the resolution, frame rate, and compression type (H.264, H.264+ or H.265) and when the camera auto changes the stream it can cause the picture not to show up.
To fix the Reconnecting.Error Code HCNetSDK.dll[91] error code, open up the iVMS-4200 software, go to Tool, and then System Configuration. Access the Image section and untick Auto-change Stream Type (check the picture below).
This should do the job and you should be able to see your cameras on iVMS-4200 software. If not, to reboot the software, or even your computer.
