Why this message (error initializing: The certificate /usr/share/rhn/RHNS-CA-CERT is expired) is logged in messages ?

Issue

• Why this message (error initializing: The certificate /usr/share/rhn/RHNS-CA-CERT is expired) is logged in messages ?

Feb 2 12:08:43 wmxxxxxxx : error initializing: The certificate /usr/share/rhn/RHNS-CA-CERT is expired. Please ensure you have the correct certificate and your system time is correct.
Feb 2 12:08:44 wmxxxxxxx : error initializing: The certificate /usr/share/rhn/RHNS-CA-CERT is expired. Please ensure you have the correct certificate and your system time is correct.

• Can not login to custom portal and after 1 hour, message is disappeared.

[root@1 ~]# grep After /usr/share/rhn/RHNS-CA-CERT
            Not After : Aug 26 02:10:55 2013 GMT
            Not After : Feb 24 21:07:08 2020 GMT

[root@2 ~]# grep After /usr/share/rhn/RHNS-CA-CERT
            Not After : Aug 26 02:10:55 2013 GMT
            Not After : Feb 24 21:07:08 2020 GMT