Why ? Rebel sl2 "not available because of the associated function's setting"

[Eliza2018]

Re: Rebel SL2--Page 114 of the user manual.

With the lens focus mode switch set to <AF> and the Mode Dial is set to a Creative Zone mode, I cannot select the AF operation.  I get the following message, under Shoot menu 1,  after clicking AF operation, no matter which Mode I choose -- M, Av, Tv, or P.  What am I  missing?

 Message:  "not available because of the associated function's setting."

[Eliza2018]

Just found the answer.

You cannot select the AF operation, when the drive mode is set to silent shooting.