Commerce Paypal WPP Sandbox: cURL error: SSL connect error
Ran this past some Paypal support personnel. They echoed both the author of the question and Nick in the comments.

Paypal reviewed the error and offered a link to this resource, which I will quote in part:


  PayPal is upgrading the protocols used to secure all external connections made to our systems. Transport Layer Security version 1.2 (TLS 1.2) and Hypertext Transfer Protocol version 1.1 (HTTP/1.1) will become mandatory for communication with PayPal in 2016. You will need to verify that your environment supports TLS 1.2 and HTTP/1.1, and if necessary make appropriate updates.
  
  PayPal is in the process of upgrading the SSL certificates used to secure our web sites and API endpoints. These new certificates will be signed using the SHA-256 algorithm and VeriSign's 2048-bit G5 Root Certificate. You will need to ensure that your environment supports the use of the SHA-256 signing algorithm and discontinue the use of SSL connections that rely on the VeriSign G2 Root Certificate.
  
  If you are using PayPal’s Instant Payment Notification (IPN) service, you will need to ensure that HTTPS is used when posting the message back to PayPal for verification. HTTP postbacks will no longer be supported.


Related Drupal.org Issue: https://www.drupal.org/node/2616730#comment-10782646

So, it seems, Paypal is upgrading lots of their security requirements for 2016. I highly recommend you investigate deeper with Paypal's support service to see if they can make a recommendation on next steps for you.