Hi @Etay Shaul,
Welcome to the Community, we’re happy to have you here! Love that you’re using custom fonts to personalize your email branding!
Our Help Center Documentation will walk you through step-by-step on how to add Adobe Fonts in your Email Template. To first walk through the troubleshooting process, I would ensure eveything in your custom font coding is correct per the documentation. It should be noted that you will need to copy the URL from the custom font you wish to import into the example code where it says
('INSERT_FONT_URL');
and change the
font-family: INSERT_FONT_NAME
to match your desired font.
Additionally, you do not need to change every block to you intent to use to include this custom font code. Anything that is add in the ‘p tag’ of the code should affect the whole ‘page’ of the email template. This code will need to be added into the first text block of your template. As shown below.

I can see that you have also shared you question with support and have found a solution! Finally, I would recommend gaining more insight about custom fonts by checking out these other posts about the same subject to build on your product knowledge!
Thanks for participating in the Community!
-Taylor