@Crea.campa you're mentioning customers. If you want to send an email to recent customers who just ordered something you could best use the placed order event instead of subscribes to newsletter. 

Subscribes to newsletter is specifically for people who signed up through a popup or footer on the page and confirmed their double opt-in email.

Hope that helps.

Hi, 

Yes sorry for my bad explanation. :) 

The problem is that the email flow i create for customers who subscribe to the newsletter do not wort. 

In fact, the mail is not sent to the customers

I don’t know why

thank you 

Hi @Crea.campa,

Thank you for sharing your question with the Klaviyo Community.

Can you tell me if these users are a part of the newsletter or not?

If they are not showing up on the list at all, I recommend looking at the post here for the solution. If they are being added to the list, I recommend looking at this post, specifically the 2nd part of the solution referencing smart sending: 

Let me know if you are still having trouble after this!

Thanks and have a great weekend.