addlistsubscribersinbulk and automation

we have an api that call your service addlistsubscribersinbulk and in the list for suscription we have an automation for register, that it should send a email to the contacts when come in the list.

With the "normal" introduced users the automation work properly. But with users introduced by api dont work

Why this happen?

How can we send emails to this users?

Thanks