Sometimes while working with the facebook php sdk, especially when making API calls  using the SDK you may come across the following error:

SSL certificate problem, verify that the CA cert is OK…… SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

Generally this happens if the bundled certificate file you are using that came with the PHP SDK download is somehow out dated or no more valid.

facebook_php_sdk_src_folder

So the quick solution is to download the latest PHP SDK and replace your existing “fb_ca_chain_bundle.crt” file present in the src folder of the PHP SDK with the latest one. You can get the latest SDK from their github repository at https://github.com/facebook/facebook-php-sdk

Just by updating this file, the error will be resolved.