New Ticket Auto-response is not working for customer Ticket#4776021

Hi, As I wrote in the title, New Ticket Auto-response is not working for customer. It works fine for domains that I have not registered in the system as a customer. I am using my own domain as the reply address. When I open a ticket they advise me to use sd-noreply@itariannotification.com instead. But I think this is not the solution and I want to use my kemdi domain. It also works fine for not already my customer. Annoying.

Anyone experiencing this situation?