curl: (60) Peer certificate cannot be authenticated with known CA certificates

Today I got this message

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.

I have COMODO SSL cert installed, and everything was ok, until this morning.
How do I fix this, without turning off curl's verification.

try this
yum update ca-certificates

if that doesn't help then
yum reinstall ca-certificates