resolved - Remote Certificate has expired, NSS error -8181

When trying below curl command for SSL cert, error occurred:

[test@host1 ~]$ curl -v -X GET -u user:pass https://example.com/v1/api.sh
* About to connect() to example.com port 443 (#0)
*   Trying 192.168.247.61... connected
* Connected to example.com (192.168.247.61) port 443 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
*   CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none
* Remote Certificate has expired.
* NSS error -8181
* Closing connection #0
* Peer certificate cannot be authenticated with known CA certificates
curl: (60) Peer certificate cannot be authenticated with known CA certificates
More details here: http://curl.haxx.se/docs/sslcerts.html

curl performs SSL certificate verification by default, using a "bundle"
 of Certificate Authority (CA) public keys (CA certs). If the default
 bundle file isn't adequate, you can specify an alternate file
 using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
 the bundle, the certificate verification probably failed due to a
 problem with the certificate (it might be expired, or the name might
 not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
 the -k (or --insecure) option.

However, the cert had not expired (it's Aug 2018):

 [test@host1 ~]# echo | openssl s_client -connect example.com:443 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | openssl x509 -noout -dates
 depth=2 C = US, O = DigiCert Inc, OU = www.digicert.com, CN = DigiCert Global Root CA
 verify return:1
 depth=1 C = US, O = DigiCert Inc, CN = DigiCert SHA2 Secure Server CA
 verify return:1
 depth=0 C = US, ST = California, L = Redwood City, O = Oracle Corporation, OU = Oracle OCI SALT-LAKE-CITY, CN = example.com
 verify return:1
 DONE
 notBefore=Dec 13 00:00:00 2017 GMT
 notAfter=Dec 13 12:00:00 2018 GMT

After some debugging, it's found the system date was "2000", and after setting the correct system time to 2018, the issue got resolved.

Good Luck & Best Wishes