Hey P,
It should work if you follow Emmanuel’s steps in this post: [Solved] Help adding font - #2 by emmanuel.
When you copy the links and paste them, either in the css file (with the link to the otf-file) or in Settings - General (the CSS file path), don’t forget to remove the last part of the link, everything after the file extension (the red part):
If you do this, it will work:
Hope this helps!