Why does email templates get low sales?

I remember 2 years ago when I was designer and we’re in team who created email templates that sales were bigger.

Now that I know how to code I wanted to try out in this area but sales are really low.

Why’s that? Since I was 2 years away from this area any explanation would be helpful :slight_smile:

There have been many changes in design templates since 2 years.
I wanna asked my sites thema before but nobody replied. https://www.seodahisi.com/ . Is there anybody have an idea about this website?