Quick Answer
SSL errors can come from expired certificates, hostname mismatches, incomplete chains, outdated TLS, or redirect problems.
Step-by-Step
- Check the SSL certificate for expiration date, hostname match, issuer, and validity.
- Review TLS version support and look for outdated or unsupported protocols.
- Inspect redirects to make sure HTTP routes cleanly to HTTPS without loops.
- Check security headers after HTTPS is working so browser protection is stronger.
Recommended Workflow
Open the most relevant calculator or utility first, enter a realistic starting point, then use the supporting tools to check assumptions, clean inputs, or prepare the final output.
FAQs
What does a hostname mismatch mean?
It means the certificate was not issued for the exact domain being visited, including subdomain differences.
Should HTTP redirect to HTTPS?
Yes. Public websites should normally redirect HTTP traffic to the secure HTTPS version.