There are two main problems to the error of Reconnecting it is not supported by the device error code hcnetsdk.dll 91 in your IP camera.
The easy and fastest solution is to use the PoE cable and turn the auto change stream off.
Remember that when using the PoE power supply, it is essential to follow international standards. (IEEE 802.3at and IEEE 802.3af). Each one has a punctual voltage for the cameras. Therefore, please advise when obtaining it to use the correct cable.
This power supply allows to use up to 100 meters and provides a better power supply. but if you are within 40 meters you can opt for a passive PoE cable.
To prevent this error code hcnetsdk.dll 91 only you have to open the ¡VMS-4200 to reconfigure the parameters.
Just login into the camera, go to the upgrade and maintenance menu.
But if all this don’t work, just try to restart the ¡VMS- 4500
It is fundamental to have the last firmware to make sure that works good to avoid the Error Code HCNetSDK.dll[91].