Cannot authenticate NTAG216 password protected block using winscard libarary

[nomibashir015]

I am using an ACR122U NFC reader to password protect an NTAG216 NFC block. I think I have managed to set the password correctly, but I cannot authenticate and change the block afterward. My code for authenticating looks like this:

I set password "1234" and Pack "OK".

public int Authentication(string Password){
 
   if(connectCard()){
      ModWinsCard.SCARD_IO_REQUEST Request;
      Request.dwProtocol = Protocol;
      Request.cbPciLength = System.Runtime.InteropServices.Marshal.SizeOf(typeof(ModWinsCard.SCARD_IO_REQUEST));
 
       ClearBuffers();
 
 
       SendBuff[0] = 0x1B; //PWD_AUTH (See data sheet)                         
       SendBuff[1] = (byte)Password[0];
       SendBuff[2] = (byte)Password[1];
       SendBuff[3] = (byte)Password[2];
       SendBuff[4] = (byte)Password[3];
 
       byte[] receivedUID = new byte[256];              
       int outBytes = receivedUID.Length;
       int status = ModWinsCard.SCardTransmit(hCard, ref Request, ref SendBuff[0], SendBuff.Length, ref Request, ref receivedUID[0], ref outBytes);
 
     }
    return status;
}
 

This should send the PWD_AUTH command to the NTAG216 with the Pwd. I expected to receive an error if the password is wrong or two bytes with the PACK if the password is correct. But SCard_Status is SCARD_S_SUCCESS and outBytes is 0 afterwards. And if I try to write to the block I get an error.

I am having trouble finding any examples showing how to do this. Can anyone see what I am doing wrong?

[Rabbit]

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