[Solved] Issued certificate has expired. (client certificate problem)

Problem: $ wget https://www.openssl.org
...
ERROR: cannot verify www.openssl.org's certificate, issued by '/C=US/O=Let\'s Encrypt/CN=R3':
  Issued certificate has expired. $ curl https://www.openssl.org
curl: (60) SSL certificate problem: certificate has expired
Fix:

1. Run
 $ sudo dpkg-reconfigure ca-certificates
2. Select 'ask'

3. Uncheck items below (use Space key to remove the *)
 - AddTrust_External_Root
 - DST_Root_CA_X3

4. Tab and OK