Guides: fixing what the checks find
What to do when a check finds something. Each guide says what was tested and what wasn't. Or run a free check.
Your site shows NET::ERR_CERT_DATE_INVALID. What now?
Your site shows NET::ERR_CERT_DATE_INVALID? Check whether the certificate expired, then fix it on your host, CDN or server. Commands included.
Missing security headers: how do you fix them?
A scan says security headers are missing? What each one does, the lines to add on nginx and Apache, and how to roll them out without breaking pages.
What happens when a domain expires?
What happens when a domain expires: when the website and email stop, how long you can still renew, and when others can register it. From ICANN policy.