SSolution 1: Check Font Files and Paths
Glyphicons use font files that must be correctly loaded by the browser.
Verify that the font files exist in the expected location relative to your CSS:
@font-face {
font-family: 'Glyphicons Halflings';
src: url('../fonts/glyphicons-halflings-regular.eot');
src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons-halflingsregular') format('svg');
}
Common issues:
Files missing from the fonts/ folder.
Browser fails to load fonts due to mimetype issues (check in Chrome DevTools → Network tab).