Firstly, make sure your server is running recent versions of both PHP and the cURL library.
Then try increasing the server memory limit. You can try doing this by opening your website with an FTP client and changing the value of memory limit in “define('WP_MEMORY_LIMIT', '256M');” in wp-config.php file. If this fails, you can ask our support team to increase the PHP memory for you.
Finally, contact us to check if there are any firewall/security modules that could be blocking the outgoing cURL requests.