I have an eShop and I’m having trouble with online payments. What could be going on?

In case you have an eShop on a Linux server and you are having difficulty with your customers' payments, then most likely you need to make some changes to your code in order to solve the problem.

Linux Servers running CentOS 7 use curl with NSS, not OpenSSL. In the NSS implementation there is no alias 'TLSv1' which gives the ciphers needed, while it normally exists in the OpenSSL implementation. The ciphers in both cases exist normally and there is no difference in their functionality.

- In case you use Vivapayments:

Replace the line in the code
curl_setopt($session, CURLOPT_SSL_CIPHER_LIST, 'TLSv1');
with the following:
define('CURL_SSLVERSION_TLSv1', 1);
curl_setopt( $session, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);

- In case your eShop is set up in Magento:

The error message you receive is the following: Unknown cipher in list: TLSv1

in the makeRequest function in the file downloader/lib/Mage/HTTP/Client/Curl.php replace it

$this->curlOption(CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);

with the following:

define('CURL_SSLVERSION_TLSv1', 1);
$this->curlOption(CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);