Can not export HTML email with background?

Newbie Figma user here. It’s my very first time using Figma. I try to export an email to HTML, thanks to emailify plugin i managed to that but there is a slight problem. Background image won’t show up when i try to preview it with online html viewers. I have limited knowledge about this field so i could be missing something basic pls EILI5 thanks!!

You can try exporting your email using another plugin like Ampier Email Generator.
If the problem persists, please provide the html code or your layout