Think of it like dialing a phone number: If you forget the area code (invalid parameter), the call fails. Similarly, the SDK function expects very specific data structures—if you supply a NULL pointer, a wrong buffer size, a corrupt IP address structure, or an incorrect data type, the function refuses to execute and returns error 9.

#define NET_DVR_PASSWORD_ERROR 9

This error rarely appears out of nowhere. It is usually triggered by one of the following scenarios:

Ensure the device and the viewing computer are on the same subnet.