SSL certificate guides

Short, practical answers for when a certificate is about to expire or already causing trouble.

How to check when an SSL certificate expires Three ways to see a website's SSL/TLS certificate expiry date: in the browser, with one openssl command, or with a free online checker. Works for any port. SSL certificate expired: why it happens and how to fix it Your site shows "certificate expired"? Find out which certificate is really being served, renew it, reload the server and stop it happening again. Certificate name mismatch (ERR_CERT_COMMON_NAME_INVALID): causes and fixes Why a valid certificate still shows a name mismatch error: missing names, wildcards that cover only one level, www vs. the bare domain, and the wrong server answering.

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