Hi @SSG NB!
First, I would ensure that you are following the steps outlined in our Help Center article:
Imported fonts, sometimes called self-hosted fonts, are recommended only for senders who have access to a developer. To use an imported font, you’ll first need to host the font, either on your servers or using a font-hosting service. Make sure to enable Cross-Origin Resource Sharing (CORS) by setting the Access-Control-Allow-Origin header to *, so the font can be accessed by your recipients’ inboxes. Learn more about CORS.
Once you’ve successfully hosted the font, click Import Font in the Add Font modal and paste your hosting URL into the Source address field. Add in your font’s name, weight, and style to the appropriate fields.
Finally, choose a fallback font and click Add Font.
The step that is often forgotten is to enable CORS, as mentioned in this Community post:
I hope this helps, and thanks for using the Community!
Best,
Brian