For angular-cli and webpack users I suspected that there is some issue while importing the fonts in css file , so please also provide url location encoded with single quotes as following -
@font-face {
font-family: 'some_family';
src: url('./assets/fonts/folder/some_family-regular-webfont.woff2') format('woff2'),
url('./assets/fonts/folder/some_family-regular-webfont.woff') format('woff');
font-weight: normal;
font-style: normal;
}
This post might be old , but this is the solution which worked for me .