SSL Certificate Chain Debugger
When a browser says the certificate is not trusted, this shows exactly which part of the chain is wrong.
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What this tool checks
- Every certificate in the chain with validity and issuer
- Hostname match against the certificate names, including wildcards
- Missing intermediate certificate
- Self-signed, expired or not yet valid certificates
- SHA-1 signatures, short RSA keys, excessive validity
- Negotiated protocol and cipher
How to read the result
Each finding is explained with a fix. A missing intermediate is the most common cause of errors that appear on some devices and not others: install the full chain (fullchain.pem) on your server.
Terms explained
Frequently asked questions
Why does my site work in Chrome but not in other clients?
Browsers can fetch a missing intermediate certificate; many tools and apps cannot. Serve the complete chain.
What is a name mismatch?
The certificate does not list the hostname you visited. Reissue it with the right names (SAN entries).