Mask Characters for automations email

I want to send by automations email Bank card data but I don’t send this number complete.
I want to mask this field to show in the automation mail with this format XXXX XXXX XXXX 1234
I don’t want to send by email the complete number of this card.
I made a field Bank Card with the numbers complete
I made another formula field named “Mask Card” with the formula REPLACE({Bank Card},1,15,"XXXX XXXX XXXX ")
Into the view this numbers it show well XXXX XXXX XXXX 1234
but when I insert the field Mask Card into email automation only send into this email xxxx
Anybody can heklp me?