Unable to Unlock macOS Lock Screen via UltraVNC from Windows

[LOHIT]

Goal: Establish a remote desktop connection to a macOS machine from a Windows system using UltraVNC.

Setup Details:

Source (Client): Windows machine
Destination (Server): macOS
Software: UltraVNC Viewer
Steps Followed:

Selected Direct connection using the macOS IP address.
Entered the connection password when prompted.
Successfully connected and reached the macOS lock screen.
Attempted to unlock using keyboard inputs (Enter, space, letters, numbers, etc.)
Issue:

The macOS lock screen is visible, but keyboard inputs are not working.
Unable to unlock the Mac—screen remains stuck on the login page.
Mouse moves normally, but typing has no effect.
Expected Result:
Should be able to input the password and unlock the macOS session.

Actual Result:
Keyboard inputs are not recognized on the macOS lock screen.

Additional Notes:
From another Windows system (using same UltraVNC), it works properly.
Tested multiple keys, still no response.

Request
Looking for guidance on how to enable keyboard input on macOS lock screen using UltraVNC.
Is there any configuration or security setting required on macOS for VNC password logins?

Thanks in advance!