Cannot communicate securely with peer: no common encryption algorithm(s)

Posted on July 17, 2017

Hi there, I have a question, my vps Centos 7 works fine but I recently upload a php script that allows payments with paypal via REST, unfourtnately, always receive next exception: Fatal error: Uncaught exception ‘PayPal\Exception\PayPalConnectionException’ with message ‘Cannot communicate securely with peer: no common encryption algorithm(s).’ in *****/****/paypal/paypal/rest-api-sdk-php/lib/PayPal/Core/PayPalHttpConnection.php:137

I tested the script in a couple of servers more and everything works fine, I don’t know if there’s a configuration I’m missing. Can anyone help me with this? I don’t know what can be the problem.

Greetings!

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Flamber Hansen

July 18, 2017

Accepted Answer

@luisroc

I’m not sure, but I guess PayPal maybe does a reverse check. And if they do, then yes, a self-signed certificate is not allowed. You either need to use Let’s Encrypt (which is free) or buy a certificate.

And according to checking your certificate, it states that you’re running OpenSSL/1.0.1e-fips in Apache/2.4.6, which is probably the reason why you’re getting the error, since that version of OpenSSL is old and insecure.

Flamber Hansen

July 17, 2017

Hi @luisroc

Which version of PHP, cURL and OpenSSL are you using? My guess would be that that one of these libraries are outdated and using an old algorithm (SSL or TLSv1) to try to communicate with PayPal, which they don’t allow.