What to Check When Your HTTPS Certificate Goes Wrong

https://thestatusdesk.quantlynix.com/posts/what-to-check-when-your-https-certificate-goes-wrong

If your HTTPS certificate throws a warning or shows as invalid, first check its expiration date—many issues come from simple expiry. Then verify that the certificate matches your domain exactly, including the www prefix if needed, and ensure your server's time and date are correct, as mismatched system clocks can trigger false alarms.