Hi there @Certa, 

Happy to help! 

You are seeing this message before your welcome flow messages after form submission becasue the list conneted to your form and Welcome Flow are set to double opt-in. When a list is set to double opt-in means that we confirm a second time that a user wants to be added to this list. 

I would check out our documentation on why this is considered best practice or how to change your list’s settings to single opt-in if you choose. Here are some insightful threads of others discussiong the pros and cons of double opt-in in the Community that you might find insightful! 

Finally, I’d check out these resources to gain more insight!

• Getting Started with Klaviyo Academy Course
• Product Certification Academy Course
• Level Up with Klaviyo  

Hope this helps! 

-Taylor 

Thanks for the help :)

Where can I customize that page so it's not so plain?

Thanks again 

I’ve found it