xbee sleep mode

my query is regarding cyclic sleep period. when i am giving 0 as the cyclic sleeping period it shows error. (indicated in red) but in the manual it is given that cyclic sleeping period can be given from 0 to 68bo. please clarify. kindly guide me to over come this hudrdle.

I don’t know which manual you are looking at, but in mine the sleep period, AT command “SP”, requires values between 0x20-0xAF0.