I hadn't used Emacs for a few weeks and when I started it up I discovered issues with certificate information for elpa, melpa and orgmode. When I launch Emacs I get the following message:
The TLS connection to elpa.gnu.org:433 is insecure for the following reasons:
- certificate has expired
- certificate could not be verified
When I look at the details the certificate issuer is Let's Encrypt. I read that the root certificate for Let's Encrypt expired in September and I wonder if that's the issue? This problem wasn't happening the last time I started up Emacs at the beginning of September.
The trouble is, I don't know how to circumvent this. I've installed OpenSSL and tried to point gnutls-trustfiles to the certificate file in that to see if it helps but that hasn't changed anything. I'm on Windows (Emacs 27.2) and it's difficult to find resources on this.