Remote power supply control(TDK lamdaZ+) with VISA, but not working code is shown below

case EVENT_COMMIT: // a button event
            
            /* Begin by initializing the system*/
            status = viOpenDefaultRM(&defaultRM);
            if (status < VI_SUCCESS)
            {
                /* Error Initializing VISA...exiting*/
                return -1;
            }
            /* Open communication with Serial Port 1*/
            /* NOTE: For simplicity, we will not show error checking*/
            status = viOpen(defaultRM, "ASRL5::INSTR", VI_NULL, VI_NULL, &instr);
            /* Set the timeout for message-based communication*/
            status = viSetAttribute(instr, VI_ATTR_TMO_VALUE, 5000);
            /* Lock the serial port so that nothing else can use it*/
            status = viLock(instr, VI_EXCLUSIVE_LOCK, 5000, VI_NULL, VI_NULL);
            /* Set serial port settings as needed*/
            /* Defaults = 9600 Baud, no parity, 8 data bits, 1 stop bit*/
            status = viSetAttribute(instr, VI_ATTR_ASRL_BAUD, 9600);
            status = viSetAttribute(instr, VI_ATTR_ASRL_DATA_BITS, 7);
            /* Set this attribute for binary transfers, skip it for this text example */
            /* status = viSetAttribute(instr, VI_ATTR_ASRL_END_IN, 0); */
            /* Ask the device for identification */
            status = viWrite(instr, "*IDN?\n", 6, &retCount);
            status = viRead(instr, buffer, MAX_CNT, &retCount);
            /* Unlock the serial port before ending the program*/
            status = viUnlock(instr);
            /* Your code should process the data*/
            /* Close down the system */
            printf("%s",buffer);
            status = viClose(instr);
            status = viClose(defaultRM);

Please help correct my mistakes. i just want to get the Status "OK" from power supply . I tried with Hyper terminal and works fine