It seems likely that the issue lies with your path or URL:
src: url("/MODERNA.TTF")
This suggests that you may be entering a directory named 'MODERNA.TTF' rather than a file.
As mentioned by @Mik, the correct declaration should work fine unless the file cannot be found.
Depending on the structure of your HTML/CSS files, it should look more like this:
(provided that your font file is in the same directory as your CSS.
@font-face {
font-family: 'Moderna';
src: url('MODERNA.eot?') format('eot'),
url('MODERNA.woff') format('woff2'),
url('MODERNA.woff') format('woff'),
url('MODERNA.ttf') format('truetype'),
url('MODERNA.svg#svgFontName') format('svg')
}
Additionally, remember that referencing font files via @font-face is case-sensitive (with some exceptions).
So make sure to double-check if your font file name truly uses uppercase letters (MODERNA.TTF or moderna.ttf).