Common Causes Behind SSL/TLS Errors

Certificate problems stem from various sources, often overlapping in complex ways. Expired certificates remain the most frequent culprit, occurring when administrators forget to renew certificates before their validity period ends. Mismatched domain names create errors when certificates are issued for www.example.com but users access example.com, or when wildcard certificates don't cover necessary subdomains.

Server misconfiguration frequently triggers SSL errors through incorrect certificate installation, missing intermediate certificates, or protocol mismatches. Time synchronization issues between servers and clients can cause valid certificates to appear expired or not yet valid. Mixed content warnings arise when secure pages load resources over unencrypted HTTP connections, breaking the security model.

Self-signed certificates, while useful for development, trigger warnings in production environments because browsers cannot verify their authenticity through trusted certificate authorities. Certificate chain problems occur when intermediate certificates aren't properly installed, breaking the trust path from the server certificate to trusted root certificates in browsers.