I noticed my Amazon S3 backups weren’t running lately using backwpup for wordpress.

Took a little digging, but I had to take the certificate verification out of the amazon aws php api.

wp-content/plugins/backwpup/libs/aws/lib/requestcore/requestcore.class.php: Commented out line 614:

//curl_setopt($curl_handle, CURLOPT_TIMEOUT, 5184000);

Changed line 624 and 625 to false:

curl_setopt($curl_handle, CURLOPT_SSL_VERIFYPEER, false);         curl_setopt($curl_handle, CURLOPT_SSL_VERIFYHOST, false);

Ended up working great after that.