# Fix SSL Errors – NET::ERR_CERT, Mixed Content & Cloudflare

SSL certificate errors, insecure site, mixed content or Cloudflare 525? Let's Encrypt, renew cert & HTTPS troubleshooting.

**Quick answer:** Fix SSL errors with a valid **Let's Encrypt certificate**, correct **Cloudflare SSL mode** (Full strict) and no **mixed content**.

**If you landed here:** Browser warns "Your connection is not private", Cloudflare shows 525/526 or padlock missing.

## Error → fix

ErrorCauseFix

NET::ERR_CERT_DATE_INVALIDCertificate expiredRenew Let's Encrypt in panel

Cloudflare 525Origin without HTTPSSSL on server + CF Full

Mixed contenthttp:// resourcesChange URLs to https://

Setup: [Set up SSL](/en/domain/ssl-einrichten) · [Cloudflare DNS](/en/domain/cloudflare-dns)