The temporary fix for Let’s Encrypt Certificate has expired Problem
A quick way of how I fixed Certificate has expired message on my website
On 30th September 2021, the root certificate that Let’s Encrypt uses, the IdentTrust DST Root CA X3 certificate, expired
So basically, I was getting certificate has expired on Postman even after reinstalling the certificate with certbot. There are many options to fix this problem, including purchasing a new certificate from a different source, but this is a temporary quick fix that worked for me.
This issue was addressed on https://community.letsencrypt.org/t/problem-with-certificate-has-expired/161013 . I am using Ubuntu server 18.04.3 LTS for this but it should work on any Debian distro
Navigate to this location using the cd command
/etc/letsencrypt/live/ . Find your domain and cd into it, edit the
fullchain.pem file and remove the last certificate.
That’s it. Restart Apache and your error should be gone. Remember, this is a temporary fix and you should find a permanent solution to this problem.