What it is
If the certificate does not cover the exact hostname being served, for example www versus the apex, browsers warn that the connection is not trusted. The certificate has to match every hostname in use. Cert doesn’t match the served hostname.
Why does certificate name mismatch matter for AI search?
Browser warnings; broken secure access.
How do you fix it?
Issue a cert covering the exact host(s).
How do you find it on your site?
- Visit each hostname variant (apex, www, subdomains) and check for a name-mismatch warning.
- Inspect the certificate Subject Alternative Names.
- Reissue the certificate to cover all hostnames, or redirect to the covered one.
- Re-test every variant.
Which ranking and citation factors does it touch?
A mismatch breaks trust on the affected hostname, which can block crawling and access there. Coverage must match the URLs you actually serve.
What is the impact?
High. Direct.
What is the evidence?
Certificate must match the domain for valid HTTPS. Google Search Central, Secure your site with HTTPS
Frequently asked questions about certificate name mismatch
What does "Certificate name mismatch" mean?
Cert doesn’t match the served hostname.
How do you fix certificate name mismatch?
Issue a cert covering the exact host(s).