Hi Mario,
Looking at the email you sent me, you don’t have Roboto Light installed on your site.
Everywhere you think you are displaying it currently, you are not. You are displaying the Arial font.
You can see in your source code that you are loading these fonts:
https://fonts.googleapis.com/css?family=Roboto:100,100italic,300,300italic,400,italic,500,500italic,700,700italic,900,900italic&subset=cyrillic,latin,latin-ext,cyrillic-ext,vietnamese,greek,greek-ext
Nowhere in the above url are you loading a font called Robot Light.
Please advise
Peter