How to fix fatal: repository 'https://github.com/user/repo' not found in Git

Why "repository not found" instead of "access denied"?

Git hosting services intentionally use vague "not found" errors for security. Revealing that a private repository exists (but you lack access) would leak information to potential attackers. This design choice, while secure, makes troubleshooting harder.

Organization-owned repositories and SAML SSO:

If your organization uses SAML Single Sign-On, your Personal Access Token must be explicitly authorized for SSO access. After creating a PAT, click "Configure SSO" next to the token and authorize it for your organization.

SSH keys and OAuth applications:

SSH keys generated by third-party Git clients (like GitKraken) may be tied to an OAuth application. These keys require explicit organization approval if you're accessing org-owned repositories. Consider generating a standard SSH key pair independently.

Enterprise Server vs GitHub.com:

Ensure you're using the correct host. GitHub Enterprise Server installations have different URLs (e.g., github.mycompany.com instead of github.com). Credentials don't transfer between instances.

Fine-grained PATs:

GitHub's newer fine-grained Personal Access Tokens require explicit repository permissions. If you created a fine-grained PAT, verify it grants access to the specific repository you're trying to reach.