Behringer X32 mute fx

[Kiff]

I want to mute my Fx via wireless midi SLM to Behringer X32 rack mixer.
I have midi bridge installed on the SLM ipad, and also on the x32 control ipad.
How would you approach this, because i am getting no results or connection.
I would like to use midi learn on the SLM ipad to at least record the mute midi cc info,
but so far nothing.
Any comment appreciated.
Cheers
Kiff