I have a website on Squarespace and the TLS certificate is set to expire in less than 24 hours.
Issuer: C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3 Validity Not Before: Aug 10 18:38:10 2019 GMT Not After : Nov 8 18:38:10 2019 GMT
I understand that certificates from Lets Encrypt are limited to a 90 day lifetime, and that certificates are typically renewed around 60-80 days after being issued. Using certificate transparency logs I can see that Squarespace has indeed renewed the certificate, but the new certificate isn't being served by their webservers yet. I reached out to Squarespace support and got this concerning non-answer, so I'm looking to better understand the situation now.
So long as your domain is active and connected to your Squarespace website using our recommended CNAME and A records (which you are), your SSL certificate will remain valid and you do not need to worry about expiration. Your SSL certificate refreshes every 90 days.
When does Squarespace usually renew certificates, and when do they begin serving them on their webserver?