IEC 104 protocol with SBO rejected

IEC 104 protocol with SBO rejected

I configured Bay in SCADA and communicated IED with IEC 104 protocol.
While doing CB close and open, i used two step verification with command processing. I also enabled the "select before operate" checkbox in the "Control" variable properties..
With al the mentioned setup, the command processing is getting "SBO Timeout".

Kindly help me to find the reason.