Automated Email Not Going to Subscribed Contacts

Question:
Subscribed customers have reported that they are not getting an automated email after filling a form on the website. Is there a setting I am missing? TIA
Product:
Wix Editor

What are you trying to achieve:
When they fill out a form, I need all customers to get the automated email response whether they are alreadt subscribed or not.

What have you already tried:
I have looked at all the settings of my automations–triggers, email type, active status, etc.

Additional information:
It appears that alread-subscribed customers are the only ones not getting the automated email. New customers with new email addresses are ok.