Password Field validate entropy

[Cristina Sig]

Hi everyone,

I'm just having some issues on my login page.
I'm trying to validate the password field but I don't know what I'm doing wrong because I can't get the validate_entropy to display when the user enters the password.
How can I activate that option?

<form  id= "formGenerico" class="form-horizontal col-md-11" method="post">
                <fieldset>
                    {{=form.custom.begin}}
                    <div class="form-group">
                      <div class="col-md-12  inputGroupContainer">
                         <div class="input-group"> <span class="input-group-addon"><i class="fas fa-user"></i></span>
                                {{=form.custom.widget.username.update(_placeholder="Nombre de usuario").add_class('form-control')}}
                         </div>
                      </div>
                   </div>
                   <div class="form-group">
                      <div class="col-md-12  inputGroupContainer">
                         <div class="input-group"> <span class="input-group-addon"><i class="fas fa-key"></i></span>
                                   {{=form.custom.widget.password.update(_placeholder="Contraseña")}}
                         </div>
                      </div>
                   </div>

</fieldset>
</form>