I've been trying to import a custom font for MC emails. I have followed the steps from this similar discussion:

Custom font in Email content blocks

I have tried both ways - using SFTP and ContentBlock, and even pasted the Base64 code directly into the HTML. But the solution seems to not work anymore. I am encountering the error below:

The HTML of this message is approximately 986.8 KB which exceeds the limit of some mail clients. These clients can show partially rendered messages. More Info

Clicking 'More Info' will just redirect me to the documentation about Preview and Test Send, which is not that helpful:


Any idea on how to make this work?

Thanks in advance!

  • so just to be clear this isn't an error its a warning message, have you tried sending the email to see how it loads/renders
    – EazyE
    Commented Jul 25, 2021 at 14:47
  • Thanks for the reply. Yes, I have tried testing it but the font has not changed.
    – ClinttErno
    Commented Jul 25, 2021 at 17:24
  • Does the email client you are viewing it in support the font you are using? Gmail only supports two fonts for reference
    – EazyE
    Commented Jul 25, 2021 at 17:34
  • 1
    Yes, I am using Roboto Regular. Sample usage <span style="font-family:CUSTOM_FONT;">Sample Sample Sample</span> and CSS is @font-face { font-family: CUSTOM_FONT; src: url(data:font/ttf;charset=utf-8,base64,%%=ContentBlockByID(5700)=%%) format('truetype'); }
    – ClinttErno
    Commented Jul 25, 2021 at 18:44

1 Answer 1


We have successfully imported custom fonts just by adding the below code inside the style tag:

@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;1,100;1,300;1,400&display=swap');

Not using any Base64 code.

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