When assets like CSS or JavaScript fail to load on GitHub Pages, the issue often lies in incorrect paths or case-sensitivity errors. Verify that links to assets are accurately spelled and use the correct file path structure. GitHub Pages is case-sensitive, so a reference to 'Styles.css' will not match 'styles.css.' Relative paths like './assets/style.css' are generally preferred for flexibility, but if your assets are in a specific folder, ensure the structure is consistently followed across all references. If using a custom domain, check that CNAME or DNS settings don’t inadvertently block asset requests. Correcting these factors usually restores asset loading.