The problem is that you're using macOS 10.10/10.11, and one of the root certificates in your keychain has expired. Since Apple stopped supporting 10.11 in December 2019 (and 10.10 earlier than that), they haven't (and won't) issue a fix.
That root certificate is one of a few on your system, and is used to validate the "trust chain" of many SSL certificates.
Because the root certificate has expired, the trust chain can't be validated, and thus secure connections fail.
The fix is to update that root certificate. The steps I've seen are:
- Download
https://letsencrypt.org/certs/isrgrootx1.der
- Open the Keychain Access app and dragging that file into the System folder of that app.
- Find the ISRG Root X1 certificate in System and double click on it, open the Trust menu and change "Use System Defaults" to "Always Trust", then close that and enter your password to confirm the change (if prompted).
That should resolve the problem.
--
Dave Nanian
Shirt Pocket
