I have been facing this issue with the Paypal IPN since last couple of days I had this similar problem before which got resolved with the help of the post Paypal IPN: certificate verify failed
cURL error: [60] SSL certificate problem, verify that the CA cert is OK. Details:error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
it worked fine till couple of days back and suddenly started breaking the flow
I tried by setting the curl_setopt($ch, CURLOPT_SSLVERSION, 1); but it didnt helped
Any ideas what could be the possible cause ?